This report presents an analysis of aggregate Citizens Broadband Radio Service (CBRS) Spectrum Access System (SAS) data reported quarterly from April 1, 2021, to January 1, 2023. The data provide valuable insights into the growth of CBRS, the impact ...

Introduction of Fifth Generation New Radio (5G NR) systems in the US between 3700 and 3980 MHz has raised concerns about electromagnetic compatibility with airborne radar altimeter (radalt) receivers operating between 4200 and 4400 MHz. This report d...

Line-of-sight (LOS) and non-line-of-sight (NLOS), continuous-wave (CW), mobile outdoor propagation measurements were performed in the 37–40 GHz band in a small city downtown environment (Boulder, Colorado). The measurement system was optimized to pro...

Circa 1960, the National Bureau of Standards intensively studied over-the-horizon radio propagation due to tropospheric (aka forward) scatter. The results of that effort, published in the form of graphs and/or empirical mathematical functions based o...

Previously published field test results showed frequent solid state marine radar (SS-MR) interference in magnetron marine radars (M-MRs) at 0.34 nautical miles distance separation and 55 MHz frequency separation. The interference was mitigated but no...

This report describes the rationale, measurement methods, and analysis techniques for assessing Long Term Evolution (LTE) user equipment (UE) emissions in the Advanced Wireless Services - 1 (AWS-1) uplink band within the observable range of aeronauti...

This Technical Report provides details about protection of federal operations in the 5.850–5.925 GHz (5.9 GHz) band from new operations considered by the Federal Communications Commission (FCC) as part of the agency’s comprehensive review intended to...

This report describes a methodology that measures the precision of objective metrics that assess image quality, video quality, speech quality, or the overall audiovisual quality. We assess the confidence intervals of 60 subjective tests and use a con...

This report presents spectrum occupancy results for 3.45–3.55 GHz and for 3.55−3.65 GHz at sensor sites near San Diego CA (SD), Norfolk VA (NF), San Francisco CA (SF), and Astoria OR (AS). Sensors operated at the following {start date, end date, 2018...

Channel modeling often provides a basis for the design and deployment of wireless technology. Engineers design systems to operate under certain expected channel conditions. Channel models are typically based on the statistics of a collection of many ...

As part of its ongoing effort to identify candidate bands for repurposing to accommodate commercial wireless services, NTIA selected the 3450-3550 MHz band to study for potential sharing between federal systems and a variety of non-federal commercial...

This report is a case-history of the development, deployment, and operational experiences associated with 5 GHz unlicensed national information infrastructure (U–NII) devices that incorporate a detect-and-avoid approach to spectrum sharing. Such dyna...

Received signal power measurements were performed on the Common Air Route Surveillance Radar (CARSR) operating in the 1300 1370 MHz band in Cedar City, Utah, and on the Airport Surveillance Radar (ASR 9) operating in the 2700 2900 MHz band in Trout C...

This report describes emission spectrum measurements of a wireless jammer device operated temporarily inside a South Carolina state prison maximum security housing block. The measurements were intended to demonstrate the operation of the jammer in fo...

Received signal power measurements were performed on the Common Air Route Surveillance Radar (CARSR) operating in the 1300–1370 MHz band in Parker, Colorado and on the Airport Surveillance Radar (ASR 9) operating in the 2700 2900 MHz band in Plattevi...

Interference protection criteria (IPC) determine the interfering signal power a system can tolerate when sharing spectrum with other services. IPC are typically determined by measurements, but good measurements are often hindered by restrictions on e...

This report describes emission spectrum and time domain measurements of a contraband wireless device micro-jammer that was operated temporarily in four Commercial Mobile Radio Service (CMRS) bands at a Federal Correctional Institution (FCI) at Cumbe...

Spectrum is a limited resource upon which the world makes continually increasing demands. It is therefore natural and compelling to study the efficiency with which radio systems use spectrum. Spectrum efficiency studies reveal how future systems can ...

Frame erasures and background noise are two factors that can interact with speech coding to reduce speech intelligibility and thus impair public safety mission-critical voice communications. We conducted two tests of intelligibility in the face of th...

Version three of Advanced Wireless Services (AWS 3) radio systems will soon use spectrum that is adjacent to bands currently used by airborne telemetry links at U.S. government test and training ranges (TTRs). Spectrum sharing analyses need to be per...

Future spectrum sharing between high-power radars and Citizens Broadband Radio Service Device CBSD in the 3550–3650 MHz (3.5 GHz) band could expose radio frequency (RF) receiver front-end low noise amplifiers (LNAs) to high peak power radar pulse sig...

We describe the design, implementation, and analysis of a speech intelligibility test. The test included five codec modes, four frame-erasure rates, and two background noise environments, for a total of 40 conditions. The test protocol required twent...

A spectrum sharing scheme is considered in which ship-based radar stations are operating in the same spectrum band as on-shore communication transmitters, and in which the communication transmitters will cause interference to the radar receivers when...

We describe a major effort to quantify the speech intelligibility associated with a range of narrowband, wideband, and fullband digital audio coding algorithms in various acoustic noise environments. The work emphasizes the relationship between these...

Great emphasis is seen on the networking and data management aspects of spectrum monitoring, but far less attention is given to the radio frequency (RF) sensor systems used to collect the spectrum data. This report focuses on these sensor systems and...

This report describes a comprehensive series of tests that were conducted by engineers and researchers from the U.S. Department of Commerce’s Public Safety Communications Research (PSCR) program and the University of Colorado during the period of Jul...

This report describes the 3.5 GHz Study. It explains the assumptions, methods, analyses, and system characteristics used to generate the revised exclusion zones for small-cell commercial broadband systems to protect federal radar operations (ship and...

This report details a method that was developed to identify all potential forms of interference that could occur with a proposed collocation of three Federal systems in the 1675–1695 MHz frequency band. The incumbents are the National Oceanographic a...

Spectrum reallocations may place broadband radio services (BRS) near spectrum used by 2900–3100 MHz band marine radars. Interference effects from these reallocations include unwanted emissions in the radar detection bandwidth and front-end overload. ...

Spectrum reallocations may place broadband radio services (BRS) near spectrum used by 2900–3100 MHz band marine radars. Signals from the BRS base stations can potentially introduce unwanted emissions in the radar detection bandwidth and cause interfe...

Spectrum reallocations may place broadband radio services (BRS) near spectrum used by 2900–3100 MHz band marine radars. Signals from the BRS base stations can potentially cause the radar front-end to overload and cause interference. This report provi...

In response to proposals to introduce new Long Term Evolution (LTE) radio systems into the 3550–3650 MHz (called 3.5 GHz) portion of radio spectrum in the United States, a joint team of National Telecommunications and Information Administration (NTIA...

This report examines the problem of how to allocate limited network resources in a public safety LTE network for the purpose of disseminating video streams to end users. We develop a mathematical model of the network environment, including the defini...

In response to proposals to introduce new Long Term Evolution (LTE) radio systems into the 3550–3650 MHz (called 3.5 GHz) portion of radio spectrum in the United States, a joint team of National Telecommunications and Information Administration (NTIA...

In response to proposals to introduce new radio systems into 3.5 GHz radio spectrum in the United States, the authors have performed measurements and analysis on effects of interference, from a variety of radar waveforms, to the performance of a prot...

In response to proposals to introduce new Long Term Evolution (LTE) microcell Citizens Broadband Service (CBS) radio systems into 3550–3650 MHz (3.5 GHz) radio spectrum in the United States, the authors have performed measurements and analysis on eff...

NTIA is responsible for managing the Federal Government’s use of the radio spectrum. In discharging this responsibility, NTIA uses the Radio Spectrum Measurement System to collect spectrum occupancy data for radio frequency assessments. This report s...

This report presents spectrum occupancy data of the 3550–3650 megahertz (MHz) maritime radar band measured in June 2012 near San Diego. In this band, the military operates SPN-43 air marshaling radar systems with well-defined signal characteristics. ...

In response to proposals to introduce new radio systems into 3550–3650 MHz radio spectrum in the United States, the authors have performed measurements and analysis on effects of interference from a variety of radar waveforms to the performance of a ...

NTIA is responsible for managing the Federal Government’s use of the radio spectrum. In discharging this responsibility, NTIA uses the Radio Spectrum Measurement Sciences system to collect spectrum occupancy data for radio frequency assessments. This...

NTIA is responsible for managing the Federal Government’s use of the radio spectrum. In discharging this responsibility, NTIA uses the Radio Spectrum Measurement Sciences system to collect spectrum occupancy data for radio frequency assessments. This...

This report describes a modified rhyme test (MRT) conducted to characterize the behavior of digital and analog communication in the presence of background noise and moderate RF channel degradation. This is done through the use of reference systems to...

This report describes a free-field radio frequency (RF) measurement system that is currently being developed by engineers at the Institute for Telecommunication Sciences (NTIA/ITS). The objective is to provide estimates of the electrical properties o...

This report describes speech intelligibility testing conducted on the Adaptive Multi-Rate (AMR) speech coder in several different environments simulating emergency response conditions and especially fireground conditions. The intelligibility testing ...

We provide detailed descriptions of recent measurements conducted by the National Telecommunications and Information Administration Institute for Telecommunication Sciences in Boulder, Colorado. ITS engineers performed a comprehensive series of both...

This report describes the methodology and results of an investigation into the source, mechanism, and solutions for radiofrequency (RF) interference to WSR-88D Next-Generation Weather Radars (NEXRADs). It shows that the interference source is nearby ...

Measured power levels for radio frequency (RF) pulses that are frequency modulated (chirped) vary as a function of the bandwidth in which the measurement is performed; if chirped pulses cause RF interference, the power levels of the pulses in victim ...

When radiofrequency pulse envelopes are observed away from their fundamental frequency their shapes differ from those at their fundamental frequency. Off-fundamental pulse envelopes tend to exhibit spikes at their rising and falling edges with lower-...

In early 2009, the Federal Aviation Administration (FAA) became aware of interference to Terminal Doppler Weather Radars (TDWRs) that operate in the 5600–5650 MHz band and provide measurements of gust fronts, windshear, microbursts, and other weather...

This report describes one of three free-field radio frequency (RF) measurement systems that are currently being developed by engineers at the Institute for Telecommunication Sciences (NTIA/ITS). The objective is to provide estimates of the electrical...

The total radio frequency (RF) field strength is the sum of all signals incident at a given location. These signals can originate from many directions and have various polarizations. This complicates the measurement of the total RF field since common...

NTIA/ITS has developed an improved electromagnetic compatibility (EMC) analysis method that can be applied to more accurately model real scenarios for evaluating interference. The methodology described in this report can be used to conduct EMC analys...

Reliable public safety communications between system repeaters outside a building and portable radios inside a building is often not possible due to building attenuation. To circumvent this problem, increasing numbers of municipalities are requiring ...

Man-made radio noise measurements were conducted in a 1.16-MHz bandwidth at 112.5, 221.5, and 401 MHz at two residential and two business locations in the Boulder/Denver, Colorado, area. The measurement frequencies and bandwidth were selected using t...

In early 2009, the Federal Aviation Administration (FAA) became aware of interference to Terminal Doppler Weather Radars (TDWRs) that operate in the 5600–5650 MHz band and provide quantitative measurements of gust fronts, windshear, microbursts, and ...

This paper describes radio channel sounding measurements and analysis using pseudo-noise (PN) codes. It presents a channel sounding model and shows how channel measurements can be made. A measurement system is described that can be implemented using ...

In early 2009, the Federal Aviation Administration (FAA) became aware of interference to Terminal Doppler Weather Radars (TDWRs) that operate in the 5600–5650 MHz band and provide quantitative measurements of gust fronts, windshear, microbursts, and ...

Digital signal processing algorithms are commonly used to obtain radio spectrum estimates based on measurements. Such algorithms allow the user to apply a variety of time–domain windows and the discrete Fourier transform to RF signals and noise. The ...

This report describes a recent measurement effort conducted by the Institute for Telecommunication Sciences at a chamber located at the NASA Space Power Facility (SPF) in Sandusky, Ohio. The report describes the chamber and the measurement system, an...

Even under ideal circumstances, insufficient spectrum is available for assigning a unique band of frequencies to each communication system. In less ideal circumstances, when a communication system experiences outages due to equipment failure or natur...

This report describes emission–spectrum measurements of a denial-of-service (jammer) transmitter that was operated temporarily in 800 MHz and 1900 MHz cellular and PCS bands at a prison location. The jammer targeted signals indoors within a minimum-s...

When bit errors are introduced between a speech encoder and a speech decoder, the quality of the received speech is reduced. The specific relationship between speech quality and bit error rate (BER) can be different for each speech coding and channel...

This report describes emission measurements on a denial-of-service (jammer) transmitter operating in the 800 MHz and 1900 MHz cellular and PCS bands. The jammer operates at a power level of up to 100 watts in each band, repetitively sweeping a carrie...

This report presents techniques for evaluating objective video quality models using overlapping subjective data sets. The techniques are demonstrated using data from the Video Quality Experts Group (VQEG) Multi-Media (MM) Phase I experiments. These r...

The study of noise and interference in the radio environment is essential to the development of efficacious communications systems. Many of the characteristics of radio noise and interference of interest to radio system designers can be expressed in ...

The systems used for public safety speech communications must be intelligible. It is also desirable that they transmit secondary information, such as the attributes of a speaker's voice. This secondary information can allow a user to identify the spe...

This report describes field measurements to characterize Land Mobile Radio (LMR) channel occupancy of Federal bands 162–174 megahertz (MHz) and 406–420 MHz at a single location overlooking the Denver, Colorado metropolitan area. This is part of the N...

This technical report describes the results of a study exploring the effects of power-producing wind turbines on Federal Aviation Administration (FAA) air traffic control (ATC) radars. The study was performed to identify the extent to which these eff...

This report describes an experiment conducted to measure the intelligibility of selected radio communication systems when those systems are employed in high-background-noise environments experienced by firefighters. The test plan for a Modified Rhyme...

This report evaluates the efficiency of federal spectrum use, performing a study that compares the spectrum resources used by several alternative land mobile radio (LMR) system architectures employing trunked radio technology to the spectrum resource...

This report describes four Reduced Reference (RR) video calibration algorithms of low computational complexity. RR methods are useful for performing end-to-end in-service video quality measurements since these methods utilize a low bandwidth network ...

On October 14, 2004, the Federal Communications Commission (Commission or FCC) adopted a Report and Order that defined new Part 15 rules for Access Broadband over Power Line (BPL) systems. The National Telecommunications and Information Administratio...

This report describes field measurements to characterize Land Mobile Radio (LMR) channel occupancy of Federal bands 162–174 MHz and 406–420 MHz at a single central location in the Washington, D.C., area. This is part of the National Telecommunication...

An investigation of different propagation modeling methods to meet the special requirements of a short-range propagation model with low antenna heights was performed, and has resulted in the development of approaches to be taken to accurately model r...

This report describes how the current frequency assignment process influences spectrum efficiency in the federal land mobile radio frequency bands. In light of the increasing demands for land mobile radio communications, federal spectrum managers mus...

This Phase 1 report contains a description of federal agencies with GMF assignments in the 162–174 MHz band, with emphasis on their LMR systems and their use in the Washington, D.C. area. It also describes many of the mobile radio technologies used...

This report describes four Reduced Reference (RR) video calibration algorithms of low computational complexity. RR methods are useful for performing end-to-end in-service video quality measurements since these methods utilize a low bandwidth network ...

This report provides results from tests that measured digital television (DTV) susceptibility to ultrawideband (UWB) interference. A test system was developed to inject interference with known characteristics into a victim receiver and quantitatively...

This report describes the results of interference tests and measurements that have been performed on radar receivers that have various missions in several spectrum bands. Radar target losses have been measured under controlled conditions in the prese...

Measured antenna patterns of an end-fed slotted waveguide antenna and a phased-array patch antenna used in maritime radionavigation radars across the frequency range 8500–10800 MHz are presented along with a measurement technique that characterizes t...

The National Telecommunications and Information Administration (NTIA) launched this two-phase study of interference protection criteria (IPC) in order to compile, explain and validate, modify or supplement the levels of protection from interferenc...

This report describes four Reduced Reference (RR) video calibration algorithms of low computational complexity. RR methods are useful for performing end-to-end in-service video quality measurements since these methods utilize a low bandwidth network ...

This report demonstrates that digital television (DTV) susceptibility to gated-noise interference cannot be predicted by interference power characteristics alone. It was found that DTV susceptibility is also dependent on temporal characteristics of t...

The wide application of radar for various functions makes large demands on the electromagnetic spectrum, and requires the application of effective frequency management for the equipment and systems involved. Requirements for certain equipment charact...

In this study, we hypothesize that ultrawideband (UWB) interference potential can be quantified in terms of UWB signal characteristics. To test this hypothesis, a test system was designed and built to inject UWB signals with known characteristics int...

The objectives of this technical study are to define interference risks from operation of BPL systems under field strength limits and associated compliance measurement procedures specified in Part 15 of the Commissions rules, identify interference ri...

In radio frequency (RF) measurements the gain (or loss) of the signal path connecting the measurement equipment to the measurement reference plane must be accounted for. This tutorial paper discusses the various definitions of gain, and how to determ...

Radiowave propagation measurements made in an urban area of Denver, Colorado, are described. Wideband, impulse response measurements were made at 4 carrier frequencies from 420 MHz to 5750 MHz. Basic transmission loss slope and delay spread statistic...

As part of the overall spectrum management process, the National Telecommunications and Information Administration (NTIA) and the Federal Communications Commission (FCC) have developed radio regulations to help ensure that the various radio services ...

This report describes laboratory measurements to determine the extent and nature of interference to Public Safety radio receivers by ultrawideband (UWB) signals. Two Public Safety radio receivers from different manufacturers were tested in the 138-MH...

Wideband channel transfer function measurements were made for a 16-element transmit and 16-element receive, multiple input, multiple output (MIMO) antenna array. The measurements were conducted using the National Institute of Standards and Technology...

The identification of linear systems from input and output observations is an important and well-studied topic. When both the input and output observations are noisy, the resulting problem is sometimes called the "errors in variables" problem. Existi...

Objective metrics for measuring digital video performance are required by Government and industry for specification of system performance requirements, comparison of competing service offerings, service level agreements, network maintenance, and opti...

A bit error model that enables simulations of the digital error performance of wireless communication links has been developed. The model development has been based on error sequences derived from waveform simulations of wireless link performance wit...

Pulsed signals in Earth station receiver spectrum bands have traditionally occurred due to unwanted emissions from adjacent-band transmitters such as radars and altimeters. Analog Earth station receivers sometimes experience interference from such em...

The objective of this report is to assess the vulnerability of telecommunications switching stations and cellular base stations to high power electromagnetic radiation generated by an RF device. Analyses, measurements, and simulations of indoor propa...

Man-made noise generated by automotive ignition, power distribution and transmission, industrial equipment, consumer products, and lighting systems degrades the performance of radio systems. Man-made noise models, derived from measurements made in th...

This addendum to NTIA Report 01-384 describes laboratory measurements on two additional Global Positioning System receivers to quantify the effects of ultrawideband interference on those receivers. The laboratory measurements were performed by insert...

Software defined radios (SDR’s) represent a departure from traditional radio design. There is some mystique about what SDR’s are, how they are designed, how they operate, and how performance is determined or verified. This report provides insight int...

A study was performed to determine the increase in ambient electromagnetic field strengths that would result from a proposal to locate a cluster of terrestrial digital television (DTV) transmission towers in proximity to the Department of Commerce (D...

This report describes the electronic, computer-based processes of creating an on-line, Web-based glossary of telecommunication terms—American National Standard, T1.523-2001, Telecom Glossary 2000. These e-mail processes or Web-based processes constit...

This report describes the objective testing of various vocoders, both singly and in different combinations of tandem configurations, to evaluate overall voice quality in an objective manner. The objective test evaluation was performed using a standar...

This report describes laboratory measurements of Global Positioning System (GPS) receiver vulnerability to ultrawideband (UWB) interference. The laboratory measurements were performed by inserting increased levels of UWB interference until an operati...

Ultrawideband (UWB) technology, useful for both communication and sensing applications, uses the radio spectrum differently than the vast majority of radiocommunication technologies. UWB systems make use of narrow pulses and time-domain signal proces...

High level electromagnetic fields can upset and damage electronics, as well as disrupt or disable computer software. Thus, high power radio frequency (RF) fields pose a threat to critical infrastructures such as telecommunications. This report examin...

Radiowave propagation measurements at Edwards Air Force Base, CA are described. These measurements were made as part of the Flexible Interoperable Transceiver (FIT) Program. The objective of the measurements is to define communication link requiremen...

Radiowave propagation measurements at Ft. Hood, Texas are described. These measurements were made as part of the Flexible Interoperable Transceiver (FIT) Program. The objective of the measurements is to define communication link requirements at 440, ...

In this study we investigated the geometric optics (GO) approximation to the fields of an incremental electric dipole above a half plane for geometries typical of wireless indoor communications. This inspection was motivated by efforts to establish a...

The Coast Guard funded the National Telecommunications and Information Administration (NTIA) to perform electromagnetic compatibility (EMC) tests between an ITU-R M. 825-3 (Characteristics Of a Transponder System Using Digital Selective Calling Techn...

This study is an update to a 1993 ITS staff study entitled "A preliminary look at spectrum requirements for the Fixed Services." That study included a description of the services provided in 30 of the Government and non-Government frequency bands bet...

This report describes measurement, modeling, and simulation methods that are used to analyze the relationship between nonlinear operation of a typical PCS portable transceiver power amplifier and battery current, out-of-band power, and link margin. F...

In recent years, there has been a significant increase in the number of reported cases of electromagnetic interference (EMI) to 3.7–4.2 GHz FSS earth stations from radar stations operating in the 3.1–.7 GHz band. The increase in reported interferen...

Dedicated short-range communication (DSRC) systems have been proposed for operation at locations across the United States in the 5850 to 5925 MHz band. To establish electromagnetic compatibility between DSRC and other 5-GHz systems, it is necessary t...

This report investigates how antenna polarization and directivity affect indoor radio channel bandwidth and signal coverage. Indoor impulse response measurements were taken at 5.8 GHz for four canonical propagation conditions: within a room, down a c...

The Coast Guard plans to operate an Automatic Identification System (AIS) Digital Selective Calling (DSC) based transponder system as part of the Ports and Waterways Safety System (PAWSS) in the lower Mississippi River. The AIS uses two duplex channe...

Mariners in the United States and other countries are experiencing interference on channels allocated to the above functions. The Radio Technical Commission for Maritime Services (RTCM) established Special Committee 117 to investigate the interferenc...

The subjective quality of speech and image information, transmitted over a high frequency radio link impaired with varying levels of interference, has been evaluated using software simulation. The high frequency radio link was also degraded by freque...

As a result of the Federal Communications Commission’s radio spectrum realignment initiative, land mobile radio manufacturers are being encouraged to incorporate narrowband and trunking technologies into their designs in order to efficiently utilize ...

This paper discusses the basic aspects of radio-wave propagation and antenna modeling in the medium frequency (MF) band. This band covers the frequencies of 300 to 3000 kHz. More specifically, we are concerned with the ground wave and the sky wave in...

An advanced antenna test bed for evaluating adaptive antennas and next-generation mobile communication systems is described. The key elements of the data acquisition system are 8 simultaneous channels, broadband impulse channel sounding, high speed a...

The National Telecommunications and Information Administration (NTIA) is responsible for managing the Federal Government's use of the radio spectrum. In discharging this responsibility, NTIA funds the Institute for Telecommunication Sciences (ITS) ra...

The maritime mobile frequency band supports maritime communications worldwide. Appendix 18 of the ITU Radio Regulations (RR) defines the channels of the maritime mobile service. These channels support a variety of communication functions including:...

New lighting devices that emit radio frequencies are being developed for commercial use. Since such devices may interfere with communication systems that utilize the radio spectrum, it is essential that the emission characteristics be carefully analy...

The maritime mobile frequency band supports maritime communications worldwide. Appendix 18 of the ITU Radio Regulations (RR) defines the channels of the maritime mobile service. These channels support a variety of communication functions including:...

Federal Standard 1037C, Glossary of Telecommunication Terms, contains more than 5800 entries defining the components of several disciplines in telecommunications technology. Use of this large glossary is enhanced with the search engine designed speci...

The transmission of E-mail over high-frequency (HF) radio channels is experiencing widespread use in the Government and military communities. This ability is made possible through the convergence of Internet and radio communication protocols, primari...

The National Table of Frequency Allocations allocate the 2025–2110 MHz band to Federal space science services and the entire 1990–2110 MHz band to the non-Federal government fixed and mobile communication services. The Federal space science services ...

Minimum acceptable speech intelligibility of land mobile radios is influenced by a number of factors. These factors include the method of modulation, transmission bandwidth, channel spacing, received signal strength, and the ability of a radio receiv...

Dedicated short-range communication (DSRC) systems, designed to enhance the efficiency of highway travel, have been proposed for operation in the 5850– to 5925-MHz band. The successful operation of these communication systems depends upon their compa...

Satellite radio system performance in the 136 to 138-MHz VHF meteorological satellite band is compromised by man-made noise external to the receiver. Methods used for predicting man-made noise power in this band are based on measurements conducted in...

Technology field trials for six personal communications services (PCS) common air-interface technologies (whose standards were developed by the Joint Technical Committee on Wireless Access) were performed at the US West Boulder Industry Test Bed (BIT...

The National Telecommunications and Information Administration (NTIA) is responsible for managing the Federal Government's use of the radio spectrum. In discharging this responsibility, NTIA uses the ITS radio spectrum measurement system and portable...

Federal telecommunications standards have traditionally been distributed in hard copy, i.e., in book form, with mandated 5-year revisions requiring a new book or new change pages for every updated edition. Distributing Federal telecommunications stan...

Multipath channels in indoor wireless communication systems exhibit a characteristic power delay profile, which can be a detriment to system performance. In this paper, we present a simplified model for calculating the decay rate of the power delay p...

Many government telecommunications needs, especially those that support National Security and Emergency Preparedness (NS/EP) missions, are becoming increasingly dependent on commercially available equipment and services. This is consistent with the g...

Complex impulse response measurements of a warehouse building were made at 5.8 GHz with a sliding correlator channel probe. These measurements were made with vertically and horizontally polarized directional antennas so performance improvement due to...

Field strength measurements of a 300-kHz Differential Global Positioning System signal transmitted at a Ground Wave Emergency Network site at Appleton, Washington were conducted. Data were acquired continually along five different routes and tagged w...

Perceived speech quality is most directly measured by subjective listening tests. These tests are often slow and expensive, and numerous attempts have been made to supplement them with objective estimators of perceived speech quality. These attempts ...

This report presents an analytic model implemented as the computer program of the transfer function of a wideband HF channel model for use in a hardware simulator. The transfer function is the basic input to the hardware simulator. The mathematical b...

A knowledge of the net inductance of the ground plane can aid in the analysis and investigation of printed circuit board emissions. In this report, we present a method, based on the concept of partial inductance, to determine the net inductance of th...

In support of the Federal Railroad Administration of the United States Department of Transportation, the Institute for Telecommunication Sciences (ITS) has completed a field spectrum utilization survey designed to examine individual channel utilizati...

The National Telecommunications and Information Administration (NTIA) is responsible for managing the Federal Government's use of the radio spectrum. In discharging this responsibility, NTIA uses a variety of spectrum measurement system to collec...

The National Oceanic and Atmospheric Administration, the European Space Agency, and the European Organization for the Exploitation of Meteorological Satellites are designing a weather satellite system that will broadcast digital weather images at VHF...

The maritime mobile frequency band supports maritime communications worldwide. Appendix 18 of the ITU Radio Regulations (RR) defines the channels of the maritime mobile service. These channels support a variety of communication functions including: p...

An interference model applicable to wireless technologies is presented in this report. Specifically, a generic methodology for cellular system self-interference modeling was developed, then applied to two proposed personal communications services (PC...

The Institute for Telecommunication Sciences has developed a computer simulation model that can be used to predict coverage and quality of service for proposed terrestrial communication systems that broadcast digital television such as local multipoi...

Signal strength measurements in the 285- to 325-kHz band were conducted on eight U.S. Coast Guard differential global positioning system beacons along the Gulf and West Coast, and on a Federal Aviation Administration beacon in Bennett, Colorado. Data...

The National Telecommunications and Information Administration (NTIA) is responsible for managing the Federal Government's use of the radio spectrum. In discharging this responsibility, NTIA funds the Institute for Telecommunication Sciences Radio Sp...

This report documents the assessment of FM subcarrier performance for Intelligent Transportation Systems (ITS) applications in three areas of interest in the United States. These areas are: 1) The Interstate 95 corridor from Richmond, Virginia, to Po...

The National Telecommunications and Information Administration (NTIA) is responsible for managing the Federal Government's use of the radio spectrum. In discharging this responsibility, NTIA uses the Radio Spectrum Measurement System to collect data ...

This report examines the additional HF spectrum requirements for the maritime mobile, aeronautical mobile, mobile, amateur, and broadcasting services previously identified by NTIA. This spectrum availability study for the five radio services was prep...

In support of the Federal Highway Administration of the United States Department of Transportation, the Institute for Telecommunication Sciences has completed a laboratory and field test program designed to independently evaluate the performance of a...

A local multipoint distribution system will essentially broadcast television signals (and perhaps more) to subscribers in small cells. It has been proposed to put such systems in the frequency band from 27.5 to 29.5 GHz where the wave length is only ...

This report presents a summary of the available measurement information on the level and statistical characteristics of the background noise environment in the frequency range of 1–3 GHz. The frequency range covers the proposed frequencies for the ne...

This report describes experiments conducted to explore the user-information transfer performance of the broadband integrated services digital network (B-ISDN), the emerging infrastructure for the global information age. These performance experiments ...

Hardware development of analog-to-digital converters (ADC's) and digital signal processors, including specialized integrated circuits, has advanced rapidly within the last few years. These advances have paved the way for development of radio receiver...

A method of high frequency (HF) radio interoperability testing in accordance with Federal Standards 1045A and 1046/1 is now available on a compact disc (CD) created by engineers at the National Telecommunications and Information Administration, Insti...

For short propagation paths, correctly representing reflections of electromagnetic energy from surfaces is critical for accurate signal level predictions. In this paper, the method of homogenization is used to determine the effective material propert...

The results of a series of data communication tests, which define the digital end-to-end performance of the Advanced Communication Technology Satellite (ACTS), are presented. The experiment consisted of a test set characterization to determine the ef...

NTIA is responsible for managing the Federal Government's use of the radio spectrum. In discharging this responsibility, NTIA uses the Radio Spectrum Measurement System to collect data for spectrum utilization assessments. This report details such a ...

This engineering manual describes a user–friendly and menu–driven computer program called the Jammer Effectiveness Model (JEM). The models used in JEM to analyze the effectiveness of a jammer in jamming a receiver/transmitter pair or network of recei...

The impulse responses of radio transmission channels over space-earth paths were measured using the coarse/acquisition code signals from the Global Positioning System of satellites. The data acquisition system and signal processing techniques used to...

Building penetration measurements were taken simultaneously at three potential Personal Communications Services (PCS) frequencies: 912, 1920, and 5990 MHz. The continuous wave (CW) measurement system employed a fixed outdoor transmitter and a mobile ...

The six volumes of this report are: Volume 1. Overview; Volume 2. Experiment Design; Volume 3. Data Extraction; Volume 4. Data Reduction; Volume 5. Data Analysis; Volume 6. Data Display This volume is an overview of the American National Standards...

The six volumes of this report are: Volume 1. Overview; Volume 2. Experiment Design; Volume 3. Data Extraction; Volume 4. Data Reduction; Volume 5. Data Analysis; Volume 6. Data Display This volume shows how to design an experiment to evaluate the...

The six volumes of this report are: Volume 1. Overview; Volume 2. Experiment Design; Volume 3. Data Extraction; Volume 4. Data Reduction; Volume 5. Data Analysis; Volume 6. Data Display This volume explains how to conduct a data communication sess...

The six volumes of this report are: Volume 1. Overview; Volume 2. Experiment Design; Volume 3. Data Extraction; Volume 4. Data Reduction; Volume 5. Data Analysis; Volume 6. Data Display This volume shows how the data reduction phase is implemented...

The six volumes of this report are: Volume 1. Overview; Volume 2. Experiment Design; Volume 3. Data Extraction; Volume 4. Data Reduction; Volume 5. Data Analysis; Volume 6. Data Display This volume shows how to analyze a performance parameter from...

The six volumes of this report are: Volume 1. Overview; Volume 2. Experiment Design; Volume 3. Data Extraction; Volume 4. Data Reduction; Volume 5. Data Analysis; Volume 6. Data Display This volume shows how to use software that draws graphs of th...

This report provides the results of radio spectrum measurements performed to characterize the aggregate signal emissions present in the 2400–2500 MHz industrial, scientific, and medical (ISM) band and adjacent frequency bands. These measurements were...

The ability to rapidly mobilize the telecommunications industry is of concern in National Security and Emergency Preparedness planning scenarios. This report assesses the extent to which the U.S. telecommunications industry is dependent on foreign so...

The Jammer Effectiveness Model (JEM) is a Windows-based computer program which provides an integrated procedure for modeling propagation effects on telecommunication links and the effect of a jammer on communication links and networks. JEM provides t...

A broadband millimeter wave study was completed to characterize the radio channel for Local Multipoint Distribution Systems in Boulder, Colorado. The study determined characteristics for proposed 20-MHz channels centered at 30.3 GHz using two transmi...

"Orthogonal Frequency Division Multiplexing" is an interesting system architecture for high data-rate digital transmission that has been receiving renewed attention. This report is a discussion of how it works and of how it might be used to carry Hig...

This paper provides definitions of spectrum efficiency for general communication systems, then simplifies the definitions so that the spectrum efficiency of several contemporary mobile radio systems can be easily compared. A variety of systems curren...

The railroad industry has proposed an advanced system for train control. This report presents an evaluation of the system development process, with particular emphasis on the data communication system that interconnects dispatch centers, locomotives,...

The susceptibility of 3700 to 4200 MHz fixed-satellite service earth stations to interference from radar signals, and the mechanisms by which such interference can occur, are examined. It is shown that interference can occur even if all currently app...

Mobile impulse response measurements were taken in the 1850–1990 MHz band in three different macrocellular (cell radii of 5 km) environments: flat rural, hilly rural, and urban high-rise. Spatial diversity with a 15-wavelength separation was employed...

Simulation has been extensively employed to evaluate concepts included in the current generation of standards for automated high–frequency (HF) radio systems. As development proceeds from link–layer technology to network– and higher–layer technology,...

The feasibility of using radio frequencies in the super high frequency (SHF) band (3-30 GHz) for Personal Communications Services (PCS) in buildings depends on the multipath within the structure and the amount of attenuation experienced by the electr...

This report documents the development of a telecommunication strategy for 1994-2003 for the Eastern Region of the U.S. Department of Agriculture Forest Service. The Institute for Telecommunication Sciences (ITS) identified telecommunication needs, as...

The National Communications System (NCS) is responsible for defining operational infrastructures and processes that could be detrimental to the provision of telecommunications equipment and services necessary to the National Security and Emergency Pr...

This report provides the results of measurements that were conducted on a 404.37 MHz wind profiler located in Platteville, Colorado. These measurements included: radiated spectra (both high and low mode), radiated harmonic and subharmonic power measu...

This report provides results of radio spectrum measurements of 13 individual microwave ovens performed at the National Telecommunications and Information Administration (NTIA) Institute for Telecommunication Sciences (ITS). Measurements include emiss...

This report presents the results of two weeks of bi–directional high frequency radio path soundings in a trans–auroral environment between Christchurch, New Zealand, and the U.S. station, McMurdo (Black Island), Antarctica, during mid–January, 1992. ...

This report is an introduction to wavelet theory intended for the technical professional working in telecommunications. The basics of wavelet theory are presented with an emphasis on explanation of the principles and ideas involved rather than on the...

The National Telecommunications and Information Administration (NTIA) in the fall of 1992 was required by Congress to develop and commence implementation of a plan for Federal agencies to use wireless mobile technologies that are spectrum efficient a...

The Digital Emission Spectrum Model report was released in September 1993. A computer program was developed to calculate the power spectral density (PSD) and the fractional power containment bandwidth for various digital modulation techniques. The po...

Impulse response measurements were taken simultaneously in both the 902–928 and 1850–1990 MHz bands using a wideband measurement system consisting of a fixed transmitter and a mobile receiver. Four different macrocells representing typical semi-rural...

The present analysis extends the concepts and approaches discussed in [1] and [2] for determining the effective erasure or overwrite of signals on magnetic tapes, as part of a general approach to the development of new, statistical standards for this...

This report presents an analysis and explanation of the system performance calculations performed by the reliability and service probability subroutines of the Ionospheric Communication Analysis and Prediction Program "IONCAP" and an IONCAP derivativ...

The purpose here is to define the present and examine the future of telecommunications over the next ten years. Emerging and anticipated products and services are viewed from both a technical and a social impact perspective. Systems including those p...

The objectives of this report are (1) to identify and examine various divergent perspectives that exist about the technology termed network management; (2) to develop a conceptual definition and understanding of network management that is rational an...

The Federal Government Spectrum Usage in the 902–928, 2400–2500 and 5725–5875 MHz Bands report was released in February 1993. This report assesses the Federal Government spectrum usage of these three bands. Current rules and regulations, allocations,...

A discrete event simulation model for an HF Automatic Link Establishment (ALE) radio network is described. The simulation model is based on Federal Standard 1045 "Telecommunications: HF Radio Automatic Link Establishment." The simulation is used to s...

Wideband impulse response measurements were made to characterize proposed radio data channels in three indoor environments. The measurement system employed a 1.5 GHz carrier which was biphase shift key (BPSK) modulated using a 100 Mb/s pseudo-random ...

This report is the second in a series of reports which describe the development of a wideband HF noise/interference mode. The model is based on measured data and is suitable for implementation in a wideband HF channel simulator. The measured data, an...

A method of utilizing the Data Encryption Standard (DES) algorithm for linking protection in HF radios complying with Federal Standard 1045 is described. The unique DES encryption method, which permits a codebook type of encryption of 24-bit words, i...

A computer program was developed to calculate the power spectral density (PSD) and the fractional power containment bandwidth for various digital modulation techniques. The power containment capability was used to provide guidance for determination o...

Wideband propagation measurements were made in a pecan orchard in Texas during April and August of 1990 to examine the propagation characteristics of millimeter–wave signals through vegetation. Measurements were made on tree obstructed paths with and...

This is the third in a series of reports which describe a new and unique approach for modeling either narrowband or wideband high frequency (HF) channels. Although narrowband models of the HF channel have existed for many years, they are applicable t...

The Spectrum Resource Assessment (SRA) is an integral part of the National Telecommunications and Information Administration (NTIA), Office of Spectrum Management (OSM) long-range planning process related to national and international interests that ...

The error variability of received PSK (MSK), QAM and QPR modulations on digital microwave common carrier links resulting from transmitted power variations and the dispersive effects of terrain multipath using a two–ray model is analyzed. These result...

This is a supplementary fifth part to a series of reports containing tabulations and graphs of transmission loss data resulting from propagation experiments which have emphasized the UHF frequency band. The first four reports described data taken in ...

Motivated by recognized vulnerabilities of the terrestrial public networks, this report addresses the question whether an appropriate introduction of advanced satellite systems would or would not benefit the telecommunication services for the current...

Erasure "standards" employing a saturating field which clips a test sinusoidal so that its 3Qharmonic is 12 dB down from the first harmonic is seen to be incomplete. The probability of (just) detecting the erased signal, under false alarm control, is...

Spectrum usage measurements were made in several potential Personal Communication Services (PCS) frequency bands in the 600 to 2600 MHz range in five U.S. cities. Geographic dependence (within a city) of spectrum usage was determined for all of the c...

If over–the–air High Definition Television (HDTV) is to become a reality it would be useful to know the multipath characteristics of the radio channel over which it will be carried. The Institute for Telecommunication Sciences (ITS) has begun a progr...

Allocations and assignments for frequencies in the United States between 1435 MHz and 2500 MHz are reviewed and summarized. The summarized data come from the FCC data base and the Government Master File.

This report discusses the development of a wideband HF noise/interference model. The model is based on measured data and is suitable for implementation in a wideband HF channel simulator. The measured data are described and analyses performed on the ...

Rapid development of personal, portable, radio communications is expected during this decade. A primary example of this is the emergence of personal communication networks (PCN). These networks are similar to today's cellular telephone technology. Ho...

The Radio Algorithms for Integration and Design of Engineering Requirements (RAIDER) program consists of a set of modules which provide an easy to use and precise approach to the complete design and documentation of terrestrial radio links operating ...

Molecular oxygen dominates the attenuation and delay rates of dry air throughout the V band (5075 GHz). Both rates display as a function of altitude an intricate pattern which, for the most part, has never been confirmed by experiment. The collective...

The mean synchronization (sync) duration time and the mean sync acquisition times are derived and computed for the Asynchronous Transfer Mode of the proposed Broadband ISDN. These waiting times are expressed as functions of channel quality, i.e., the...

Telecommunications networks are shown to exhibit three attributes that distinguish them from each other, namely, the service offered, the functional architecture necessary to provide this service, and the hardware and software that implements this ar...

Development and testing of various implementations of High Definition Television (HDTV) require knowledge of the multipath characteristics of the radio channel over which the proposed signal will be carried. The Institute for Telecommunication Scienc...

This report describes the steps for designing experiments to quantify the performance of a communication satellite system according to the methods specified by ANS X3.l4l. Performance is described in terms of performance parameters that are user–orie...

The minimum amount of spectrum to satisfy worldwide broadcasting requirements in the high–frequency (HF) bands is estimated. This analysis provides technical bases for the U.S. allocation proposal$ being developed in preparations for the World Admini...

This report discusses a collection of microwave common carrier azimuthal antenna patterns. The patterns were digitized and stored into a uniformly formatted database. The primary application of this database is for interference prediction among commo...

This report describes an automated method of video quality assessment based on extraction and classification of features from sampled input and output video. The first subsystem of the automated video quality measurement system is the feature extract...

This report describes the results of an 18-month digital microwave radio performance and propagation measurement project that was conducted on a portion of the Defense Communications System in Germany. More than 6 gigabytes of data were collected ...

This report describes the results of an 18-month digital microwave radio performance and propagation measurement project· that was conducted on a portion of the Defense Communications System in Germany. More than 6 gigabytes of data were collected...

This report describes the results of an 18-month digital microwave radio performance and propagation measurement project that was conducted on a portion I of the Defense Communications System in Germany. More than 6 gigabytes of data were collecte...

This manual describes the functions of the TRAMCON (TRAnsmission Monitor and CONtrol) On#8211;Line software and the steps necessary to maintain the software. This document emphasizes the software semantics rather than the syntax. The structure of the...

In order to determine how effective an erasure procedure is it is necessary to examine the detectability of the remaining signal in tape noise. This detectability can be measured by the probability of correct detection of the signal, which should be ...

A summary is presented of a series of monitoring campaigns held between 1984 and 1989 to locate the sources of intentional harmful interference to the HF broadcast spectrum. The monitoring programs were organized under the auspices of the Internation...

Data from 21 ionospheric sounding stations in the northern and southern hemispheres were used to characterize the day to day variation in the critical frequency of the F2 layer of the ionosphere. Variability in the critical frequencies are analyzed m...

The Institute for Telecommunication Sciences (ITS) has performed a number of technical tasks as part of the responsibilities of the National Telecommunications and Information Administration (NTIA) for re–establishing the Pan-Pacific Educational and ...

This report provides a descriptive overview of the factors affecting the development of international value-added network services (IVANS). The paper first addresses terminology and describes the legal and regulatory environment in the United States...

This report presents a detailed assessment of the hydrologic and meteorological operations in the 162–174 MHz (VHF) and 406.1–420 MHz (UHF) bands. These operations are currently supported by hydrologic and quasi-hydrologic channel assignments in thes...

This report examines the potential for ground–based weather radar (meteorological radar) interference to digital microwave systems in the common carrier bands of 3700–4200 MHz and 5925–6425 MHz. Reported cases of interference to microwave common carr...

This report is the second report in a series of reports which describe a new and unique approach for modeling either narrowband or wideband high frequency (HF) channels. Although narrowband models of the HF channel have existed for many years, they a...

This paper discusses the design and the measured performance of a 76.8-kIn (47.7-mi) over–water 2.3 GHz microwave radio link. Since one of the terminals was located on an ocean tower, the maximum antenna height at that location was restricted to 49 m...

This report covers the first task of a three–task effort designed to explore the potential of using advanced satellite system technologies to enhance the rapid restoration of telecommunication services that may be disrupted due to traffic congestion ...

The Second Session of the High Frequency Broadcasting Conference held in Geneva, Switzerland, in February 1987, resolved a need for an improved system to plan the radio frequencies allocated exclusively to the HF broadcasting service. The Final Acts ...

The current status of fiber optic and related broadband terrestrial networks is reviewed. That includes summaries of link and switch capabilities as well as present and future standards for broadband systems. In the domain of communication satellites...

This report is a brief outline and a catalog o full power spectral densities for certain M–ary frequency shift keying waveforms. Spectral equations are displayed in graphical form for easy visualization . The spectra pertain to real signals centered ...

Propagation measurements were made in the Olympic National Forest of Washington state during October 1987 to examine millimeter-wave signal propagation through conifer vegetation. Linearly polarized continuous-wave signals at 9.6. 28.8. 57.6. and 96....

This report presents an overview of moving image (video) data compression. Because this report deals with a subtask of a major program, a limited number of the most pertinent topics and issues have been addressed. These topics include a listing of hu...

At heights between 30 and 100 km above Earth, the oxygen absorption lines near 60 GHz together with the geomagnetic field cause the atmosphere to become an anisotropic medium. This report discusses why this is so and how to compute the consequent eff...

This report provides a description of and operating instructions for Digital Line–of–Sight (DLOS) programs. These programs, which run on a desk–top computer, automate the calculations involved in design of line–of–sight microwave radio relay paths. T...

This report describes the interim results of an 18–month digital microwave transmission network performance and propagation measurement project that was conducted on a portion of the Defense Communications System (DCS) in West Germany. Only the first...

This report describes an adaptive antenna computer model that simulates the behavior of a steerable–nulling antenna processor (SNAP) in a jamming or interference environment. The model predicts the signal–to– (interference–plus–noise) ratio as a func...

This is the fourth in a series of reports describing the results of studies to determine the location of sources of harmful interference to the high frequency (HF) broadcasting service. Using observations recorded during the July 1988 monitoring prog...

Since the spectrum is a limited natural resource, the spectrum management community has a major interest in identifying spectrum conservation techniques that will provide more efficient spectrum utilization. Advances in new technology for fixed micro...

The technical and operating characteristics of meteor burst systems of importance for spectrum management applications are identified. A technical assessment is included which identifies the most appropriate frequency subbands within the VHF spectrum...

Measurements were performed in an urban-suburban environment with narrowband and wideband RF probes, which include millimeter-wave frequencies, in order to study propagation characteristics for street level paths. The primary objective of this report...

This report describes a new and unique approach for modeling either narrowband or wideband high frequency (HF) channels. Although narrowband models of the HF channel have existed for many years, they are applicable to only a limited set of actual pro...

This report details a study on the application of American National Standards X3.l02 and X3.l4l to various classes of communication satellite systems from the simple analog "bent–pipe" to NASA's Advanced Communications Technology Satellite (ACTS). Th...

The NITA Information Services Report is a study of the information services available via telecommunications networks in the United States and a number of foreign countries. It presents a review of the information services available in the United Sta...

This report describes a new technique for calculating the spectrum space used by existing frequency assignments. The Spectrum Use Measure (SUM) model determines the amount of spectrum used at a given location or the probability that a given location ...

An interactive program has been developed to evaluate the performance of medium frequency (MF) broadcasting systems. The model calculates both ground–wave and sky–wave signals. The user can select from three ground–wave methods: (1) smooth Earth, hom...

This report presents results of a multiyear data communication performance measurement program conducted at the Institute for Telecommunication Sciences, the research and engineering arm of the National Telecommunications and Information Administrati...

Important changes in the video market, particularly with respect to cable television over the last ten years, have raised several policy issues. The expanded technological capabilities of optical fibers and computers create new ways to transport a...

The Mu1itier Specification was developed to provide guidelines and recommendations for improving the durability of the communication installations necessary for National Security/Emergency Preparedness (NSEP). The application of the Multitier Specifi...

This report discusses propagation and performance measurements that were obtained over a digital troposcatter communication link between Bocksberg, West Germany, and West Berlin. The measurements were unusual because three general types of data were ...

Minimum (or "best–fit") elliptical beams of satellite antennas have been used for the planning of space services utilizing the geostationary–satellite orbit. In such a planning, beam parameters of minimum elliptical beams are necessary for all possib...

Fiber optic telecommunication systems are susceptible to both natural and man-made stress. national Security/Emergency Preparedness (NSEP) is a function of how durable these systems are in light of projected levels of stress. Emergency Preparedness i...

Fiber optic telecommunication systems are susceptible to both natural and man-made stress. national Security/Emergency Preparedness (NSEP) is a function of how durable these systems are in light of projected levels of stress. Emergency Preparedness i...

In the first section of this report, rainfall observational data are processed by least-squares curve-fitting to call attention to some of the desireable aspects of such fittin. The curve fitting techniques are illustrated for annual rainfall and wor...

The National Communications System (NCS) is responsible for defining reasonable enhancements that could be applied to commercial common carrier (or carriers' –carrier) fiber optic systems that will be leased or owned by government agencies and which ...

Laboratory measurements have been performed at 138 GHz of water vapor attenuation αx for pure vapor (H2O) and its mixtures with air, nitrogen (N2), oxygen (O2), and Argon (Ar). Temperatures ranged from 8 to 43°C, relative humidities from 0 to 95% and...

Molecular absorption lines in the millimeter-wave band make the atmosphere dispersive, thus causing the distortion of transmitted signal shapes. To better understand how severe this distortion is and what form it takes, it seems useful to examine the...

The U.S. Army Electronic Proving Ground (USAEPG) is planning the development of a new test facility to be known as the Stress Loading Facility (SLF). This facility is envisioned as an integrated and automated test capability that will generate a dens...

A useful approximate first-order characteristic function for Class C interference is obtained, for arbitrary combinations of the additive Class A and Class B nongaussian components which define Class C noise. From this, in turn, the associated first...

In order to determine the feasibility of multiple system decoders for AM stereo receivers, the Institute for Telecommunication Sciences made a series of laboratory and field tests on certain commercially available AM stereo receivers. We also made te...

This report, an assessment of the telecommunications system in the Peoples' Republic of China (PRC), identifies areas of technical cooperation in telecommunications sciences between the U.S. and China and recommends strategies for improvement and exp...

When wave propagation through a stratified atmosphere is formulated in operator theoretic terms, it becomes evident that the problem does not follow the guide of the usual examples of mathematical physics. Nevertheless, such a formulation is useful t...

A series of programs have been developed by the Institute for Telecommunication Sciences (ITS) that assist the Voice of America (VOA) to plan and operate high frequency (HF) broadcast stations. The VOA has specific broadcast bands available for use a...

Laboratory testing of proposed and new wideband (e. g., spread spectrum) high frequency (HF) systems is currently not possible because wideband HF channel simulators do not exist. Moreover, there are no validated HF channel models for bandwidth on th...

NTIA Regulatory Review Staff

This report describes a fiber optics system model and its computer implementation. This implementation can calculate the bit error ratio (BER) versus time for optical fibers that have been exposed to gamma radiation. The program is designed so that t...

The First Session of the World Administrative Radio Conference for the planning of the high frequency (HF) bands allocated exclusively to the broadcasting service held in Geneva, Switzerland, in January and February of 1984, established the technical...

An expression for the gain of a curtain array antenna over a perfectly conducting, flat Earth with no mutual impedance between elements is derived in this report. A FORTRAN computer subroutine created to calculate the expression is described here. Th...

This is the third in a series of reports describing the results of studies to determine the location of sources of harmful interference to the HF broadcasting service. Using observations recorded during the June 1986 monitoring program conducted unde...

The objective of this study is to look at fiber optics networks in a predominately functional domain and to assess their potential survivability advantages from that point of view. As a consequence, service survivability is emphasized far more than p...

Competition in the Local Exchange Market

American National Standard (ANS) X3.100 will be adopted as Federal Information Processing Standards Publication (FIPS PUB) 100 and Federal Standard (FED STD) 1041. These standards are based on CCITT Recommendation X.25 and ISO Standards 7776 and 8208...

This report presents an updated and improved noise model designed for use in the HF propagation prediction program, IONCAP. The model has, however, much more general applicability, since the frequency range 10 kHz to 30 MHz is covered. The report giv...

An automated analysis model is presented for the prediction of system performance of communication circuits that use the ground wave as the primary mode of propagation. The computer program Ground Wave Automated Performance Analysis (GWAPA) is a user...

A method of interpolation that accurately interpolates data values that satisfy a function is said to have the accuracy of that function. The desired or required properties for a univariate interpolation method are reviewed, and the accuracy of a thi...

Prediction of propagation effects (i.e., path attenuation, phase delay, ray bending and medium noise) over the 1 to 300 GHz frequency range through the clear, nonturbulent atmosphere is accomplished by combining a spectroscopic data base with a compu...

This is the second in a series of reports describing the results of studies to determine the location of sources of harmful interference to the HF broadcasting services. Using observations recorded during the January 1986 monitoring program conducted...

This report describes the mathematical models used in the ARROWS programs. These programs, which run on a desktop computer, automate the calculations involved in the design of line–of–sight microwave radio relay links. The programs calculate, tabulat...

An automated analysis model is presented for the prediction of system performance of communications circuits that use the ground wave as the primary mode of propagation. The computer program Ground Wave for Voice of America (GWVOA) is a user–friendly...

This report describes a set of receiver transfer characteristic (RTC) algorithms developed at NTIA for the analytical assessment of mutual interference effects in satellite communication services. The RTC algorithms convert the input carrier-to-inter...

The analysis technique developed and discussed in two earlier NTIA reports (Farrar, 1984; Farrar, 1983) was used in conjunction with the data obtained from a number of different countries to calculate the power flux-density (pfd) levels in the 2 GHz ...

The distribution of raindrop sizes in a given volume of air remains an unknown aspect of critical importance to the prediction of rain attenuation at millimeter–wave frequencies. Thus, in this report, the search continues for a methodology of predict...

Fritchman's single–error–state (SES) model for describing the error statistics of digital communication channels is modified to allow the prediction of error statistics as a function of the bit error rate (BER). From the data samples of a measurement...

Measured analog data showing gain as a function of angle away from the mainbeam (maximum gain) axis have been obtained for 14 models of reflector antennas designed for operation at 11/12 GHz for reception and at 14 GHz for transmission. The antennas ...

For efficient use of the geostationary satellite orbit, mutual interference among satellite systems must be analyzed in the planning stage of the systems. To conserve the transmitter power, many satellite antennas in the FSS (fixed–satellite service)...

This report is tutorial in presentation, with emphasis on the application of engineering formulations of the effects of terrain upon terrestrial microwave systems. Many of these formulas have been available for a decade and longer, but they have not ...

Comparisons of Fritchman's single-error-state model with the two-state Markov model are presented in graphical form for a number of statistical functions, e.g., the error gap distribution (EGD), the block error probability (BLER), and the probability...

New models of electromagnetic interference (EMI) have been developed by Middleton [1-11 ,48,49] over the last decade (1974–1983), which have provided canonical, analytically tractable, and experimentally well established quantitative descriptions of ...

An EHF Telecommunication System Engineering Model (ETSEM) has been developed as an aid in the design of line-of-sight (LOS) communication systems from 10 to 100 GHz. ETSEM provides tabulation of path geometry parameters and analyzes ray-path and Fres...

An experimental millimeter-wave propagation link was installed on a 1-km path in the northern California area (Gasquet) to compare rain rate and attenuation at 28.8, 57.6, and 96.1 GHz. During the monitoring period (January 26 through April 14), rain...

There has been a significant internationa1 effort to develop standards for Integrated Services Digital Networks (ISDNs) at the same time that events leading to the divestiture of the American Telephone and Telegraph (AT&T) Company were occurring in t...

The millimeter-wave behavior of rain attenuation based on recent experimental data, Jan. 1986

The results of a detailed investigation to isolate the location of sources of intentional interference to the HF broadcasting service are presented. The investigation was conducted using observations of intentional harmful interference observed at nu...

This report discusses quality–of–service (QOS) issues for telephone networks. Deregulation and divestiture have fostered increased competition in the United States in the telephone equipment and service industries. There are many economic, policy, an...

The factors that affect the design of a numbering plan for the Integrated Services Digital Network (ISDN) involved a complex interplay between existing plans, national priorities, and technical system limitations. These factors are the subject of thi...

Measurements reported are part of a study of propagation characteristics for millimeter-wave communication links operating in an urban-suburban environment. Absorption data were collected for signals propagated through some common building materials...

This report addresses the concepts, the justification, and the eventual configuration of military access areas. Many factors enter into this access area characterization effort. The key factors emphasized here are: the current telecommunications envi...

The OSI Network Layer Addressing Scheme, Its Implications, and Considerations for Implementation, Nov. 1985

This report is a study of Travelers' Information Stations (TIS) operating in the 525–535 and 1605–1615 kHz bands. It was prompted by the expansion of the AM broadcasting band from 1605 to 1705 kHz. Included is information on rules and regulations, al...

A Phase I spectrum resource assessment based upon use of the bands containing fixed and mobile services in the 947–17,700 MHz portion of the radio frequency spectrum was completed in 1984. From the total number of fixed and mobile bands, four bands (...

Several methods for estimating the potential interference from systems in the Fixed Service to Power-Line–Carrier (PLC) circuits were developed. The Numerical Electromagnetic Code (NEC) computer program, originally developed by the Navy, was used to ...

The combined communications probabilities (Cm) have been calculated for 56 Simulated Ship Positions (SSP's) in the North Atlantic to a network of 26 digital selective calling shore stations The Cm are based on individual circuit reliability data obta...

In a cooperative program, the Federal Communications Commission and the Institute for Telecommunication Sciences have begun a study of the interference fields that may arise in a ducting environment. This report gives some preliminary thoughts on how...

The determination of radio communication system performance is a matter of proper statistical treatment of both the desired signal and the real-world noise (or interference) processes. System performance is highly dependent on the detailed statistica...

Local networks, related standards activities of the Institute of Electrical and Electronics Engineers (IEEE) Project 802, the American National Standards Institute (ANSI), and other elements are presented. These elements include 1) technology choices...

This report is a spectrum resource assessment of the 1605–2000 kHz band. It includes information on rules, regulations, allocations, technical standards, frequency assignments, system characteristics, and applicable compatibility analyses pertinent t...

A practical atmospheric millimeter-wave propagation model (MPM) is updated and tested with experimental data from horizontal, line–of–sight links when there is no precipitation. The MPM computer program predicts attenuation and delay properties of mo...

The National Telecommunications and Information Administration (NTIA) and the Interdepartment Radio Advisory Committee (IRAC) require, for their management of the spectrum, technical guidance concerning the necessary bandwidth and spectral characteri...

Measured analog data showing gain as a function of angle away from the mainbeam (maximum gain) axis have been obtained for 22 types of reflector antennas designed for operation at 4 GHz for reception and 6 GHz for transmission. The antennas ranged in...

In the presence of rain, millimeter–wave propagation is acutely sensitive to the distribution of raindrop sizes along a given propagation link. This report analyzes the variability of rain attenuation prediction at microwave/millimeter wave frequenci...

Telecommunication and computer technologies are merging, stimulating such global communication projects as the Integrated Services Digital Network (ISDN) and the Open Systems Interconnection (OSI) Reference Model. The systems of standards needed to e...

The National Telecommunications and Information Administration (NTIA), in keeping with its responsibility for managing the Government's use of the radio frequency spectrum, researches particular bands when changes in national and/or international all...

Calculating the polarization angles of antennas and radio waves is necessary for analyzing the mutual interference when a linearly polarized emission is used in satellite communications. A method for calculating the polarization angle has been develo...

The Institute for Telecommunication Sciences has undertaken an assessment of the link margin required for the satisfactory performance of a direct broadcasting satellite service operating in the high frequency (HF) and in the very high frequency (VHF...

This. report is a spectrum resource assessment of the 7125–8500 MHz band. Included is information on frequency allocations, technical standards, spectrum usage, and identification of spectrum-management issues pertaining to this band. The spectrum-ma...

This report documents a spectrum resource assessment of the 1530–1660.5 MHz band. The impact of allocation changes resulting from the WARC-79 are addressed. Information is included on allocations, frequency assignments, system characteristics, and sp...

This report is a spectrum resource assessment of the Aeronautical Mobile Service between 400 MHz and 17.7 GHz, which addresses the long-range planning of this service. It presents an assessment of 15 Federal Government frequency bands that are alloca...

This report describes an interactive computer program that facilitates efficient measurement of communication system performance parameters. The program performs three primary functions: (1) determines the minimum sample size required to achieve a de...

An engineering approach to the design of optical fiber communication links to meet mandated specifications for performance and interoperability is described. The report follows and expands upon technical guidance originally developed for MIL-STD-188-...

This report constitutes a Spectrum Resource Assessment (SRA) of the band 17.7-40.5 GHz. Included is information on rules and regulations, allocations, technical standards, current and proposed usage, and planning and coordination procedures. Major is...

This report examines the use of Amplitude Compandored Single Sideband (ACSB) and/or 12.5 kHz FM (NBFM) as possible solutions to the spectrum congestion in the Government Land Mobile Service in the VHF bands. These narrowband modulation techniques are...

NTIA and member agencies of the Interdepartment Radio Advisory Committee (IRAC) have long recognized the need for a set of measurement procedures to augment the Radar Spectrum Engineering Criteria (RSEC). In light of this, a Working Party was formed ...

Measurements of radio propagation path loss were made over four paths in the 3 to 30 MHz band. The paths were of lengths up to 45 km in the Boulder, CO, area. They ranged from smooth to mountainous terrain, from open areas with few or no man-made str...

The power flux-density (pfd) limits for satellites operating in the 2025–2300 MHz frequency range were calculated. Two computer models, one developed by the Bell Telephone Laboratories (BTL) and the other by the Systematics General Corporation (SGC),...

The attenuation of a received signal on a millimeter wave (above 30 GHz) link probably will be considerably more sensitive to transmitted polarization of the signal than is the case on a microwave (below 30 GHz) link. The introduction of this report ...

Measurements of near-field mutual coupling were performed between two moderate sized microwave antennas and compared to coupling calculated using recently developed computer programs. Input data for the programs are the complex far-field radiation p...

NETWORK is an interactive computer program designed to help the National Weather Service expand the NOAA Weather Radio Network to obtain the desired coverage at minimum spectrum usage. For each active station, areas of predicted service and co-channe...

This paper describes a minicomputer-based communication system monitor used by the U.S. Department of Defense to improve the performance and reduce the operating costs of the new multi-channel digital transmission systems. A brief history of the deve...

Because rain attenuation continues to be a problem for the operation of microwave links worldwide, this report examines the behavior and the prediction of rain rate and rain attenuation·distributions on a worldwide basis. Particular emphasis is pl...

A diagnostic probe designed to investigate propagation at millimeter wavelengths was operated on 11.8 and 27.2-km line-of-sight paths near Boulder, CO. A 30.3-GHz carrier is biphase-shift-keying modulated at a 500 Mb/s with bit error rates less than ...

This report is a spectrum resource assessment of the 162–174 MHz band. Included is information on allocation, frequency assignments and agency equipment usage, along with the results of agency interviews. Present spectrum management techniques and as...

Today, three–quarters of the U.S. employment and one–half of the Gross National Product (GNP) are associated with services. In 1981, services employment predominated, for the first time, over both agriculture and manufacturing, even in the Third Worl...

Observations of the F2-region critical frequency, foF2, and values determined from,the time-dependent continuity equation for ions and electrons in the ionosphere have been used to develop a new set of numerical coefficients to represent the global v...

This report is an update of a previous report of the same title published by the former Office of Telecommunications Policy. It provides guidance to Federal system planners in securing spectrum support for proposed new or modified telecommunications ...

Since the normally assumed with Gaussian interference is the most destructive in terms of minimizing channel capacity, substantial improvement can usually be obtained if the real-word interference environment (non-Gaussian) is properly taken into acc...

The evaluation of prediction models for microwave attenuation by rainfall Jan. 1984

The neutral atmosphere is characterized for the frequency range from 1 to 300 GHz as a nonturbulent propagation medium. Attenuation and propagation delay effects are predicted from meteorological data sets: pressure, temperature, humidity, suspended ...

Analytical and empirical results concerning the relative spectrum efficiency of twogenerjc (wideband and narrowband) land mobile radio systems are presented. Graph theoretic frequency assignment techniques are used to relate spectrum usage to transmi...

American National Standard X3.102 defines a set of 21 standard parameters that provide a uniform means of specifying the performance of data communication systems and services as seen by users. This report is basically an explanation and elaboration ...

This report contains a consolidation of practical engineering equations for linear communication antennas suitable for use in the prediction and analysis of the system performance of high frequency communication equipment. The theoretical background ...

This report is concerned with the spectral representation of analog frequency modulated (FM) signals, with particular attention to frequency division multiplexing (FDM)/FM satellite communication systems. The FM spectral modeling and gaussian approxi...

An assessment of the line-of-sight (LOS) power flux-density (pfd) limits for satellites operating in the 2025–2300 MHz frequency range was conducted. Two computer models, one developed by the Bell Telephone Laboratories (BTL) and the other by the Sys...

The problem of counting the occurrences of bit errors, block errors, bit additions or deletions and block additions or deletions is considered. A general method is developed for counting such occurrences for cases when the occurrences are not excessi...

The report is a primer on Integrated Services Digital Networks (ISDN's). The ISDN concept is believed by many to be the communication means for the future information age. A number of national ISDN's interconnected together can provide a high-perform...

A diagnostic probe used to fully describe the propagation characteristics of a millimeter wave channel by nearly simultaneous recording of an impulse response, frequency spectra, amplitude response, and bit error rate is discussed. A 30.3 GHz carrier...

It is demonstrated that most of the classical raindrop-size distribution formulations give inconsistent results when used to calculate specific attenuations at millimeter-wave frequencies. For this reason, it was decided it might be desirable to subc...

Although the use of transmissions that are composed of bursts of information is not new, its application in a terrestrial environment at VHF and UHF is. The usual way of expressing the variabilities in received signal level due to propagation effects...

A radio propagation prediction computer code has been developed to permit rapid simulation of HF air-to-ground telecommunication circuits. This prediction program provides estimates of both skywave and groundwave HF propagation parameters. The skywav...

A simple model of the attenuation of millimeter waves by precipitating liquid water clouds is presented. As frequency increases from the microwave band into the millimeter wave band, the model indicates a significant increase in the relative importan...

This report describes the operation and use of the Ionospheric Communications Analysis and Prediction Program (IONCAP). The computer program is an integrated system of subroutines designed to predict high-frequency (HF) skywave system performance and...

This report describes an experiment designed to measure the performance of digital microwave radio systems in a line-of-sight (LOS) link that is subject to strong atmospheric multipath. It outlines the measurements made to characterize the propagatio...

Attenuation by the atmosphere can severely limit the use of the radio spectrum above 10 GHz for telecommunication purposes. In this report brief discussions of three mechanisms that attenuate millimeter waves in the atmosphere are presented: rain att...

In this second part of an ongoing study, the general problem of optimum and suboptimum detection of threshold (i.e. weak) signals in highly nongaussian interference environments is further, developed from earlier work ([la],[lb];[34]). Both signal pr...

A review of EIA and CCITT data interface standards identifies three generations namely: first (1960's), second (1970's), and third (1980's and beyond). The User/Network physical interference for the pending Integrated Services Digital Network is an e...

This report discusses the different types of interoperability requirements, summarizes several related research and development projects, and presents alternatives for aachieving interoperability between the Defense Communications System and the TRI-...

The multiple knife-edge (MKE) attenuation function is derived from Fresnel-Kirchhoff theory and compared with the original derivation from Furutsu’s generalized residue series. It is shown that the two methods give complex attenuations with the same ...

In early 1980, NTIA, through the Interdepartment Radio Advisory Committee (IRAC) Spectrum Planning Subcommittee (SPS), became cognizant of several new major radar systems being developed by Government agencies in the 2700–2900 MHz band. In light of t...

Price of international satellite service: COMSAT vs INTELSAT, April 1983

This report presents an overview of the 1982 telephone network technology. Many physical facilities constitute the public switched telephone network. Their respective roles in support of voice services and related traffic are reviewed. Essential inte...

The meteor burst communications model is a user-interactive computer model that predicts the reliability of a communications system that uses meteor bursts as the communications channel. The model predicts the waiting times required to complete the t...

This report is a spectrum resource assessment of the 5650–5925 MHz band. Included within is information on rules and regulations, allocations, technical standards, frequency assignments, system characteristics, and applicable compatibility analysis.

An integral equation method is presented for computing the vertically polarized field strength over irregular terrain which is covered with forest, buildings, or snow. The terrain cover is modeled as an equivalent slab, and a general computer code, W...

Comparisons of theoretical attenuation based on multiple knifeedge diffraction with measured values of median propagation loss are presented for a number of different propagation paths. In general the knife-edge predictions tend to overestimate recei...

This report describes use of the revised computer program FOOTPRINTS. The program automatically computes and plots earth footprints and service area polygons on a map projection of the earth's surface. The program can be used as a design tool to maxi...

The burning of an Atlas-Centaur rocket in the ionospheric F–region was used to determine the extent of HF propagation anomalies associated with the resultant drop in ionospheric electron content. This "ionospheric hole" grew to encompass the control ...

General Docket 81-414, Notice of Inquiry and Proposed Rulemaking, proposes allowing the Amateur Radio Service to use spread spectrum techniques in three bands. This report reviews the Docket's proposals and the public's reaction, reviews direct seque...

This report presents the results of a trial implementation of a newly developed data communication performance measurement methodology which has been proposed as Federal Standard 1043. In this experiment, a prototype data communication performance me...

The Forest Service is in the process of updating its telecommunication and information systems. Included in this update are proposed changes to the telephone systems of selected National Forests with an eye toward telephone cost reductions over curre...

PRODSIR is a procedure for computing the probability distribution of the signal-to-interference ratio in a congested radio environment. Most of the independent variables in the usual signal-to-interference equation are assumed to be random variables,...

This report presents an extensive bibliography, categorized by effect, of radio propagation through the atmosphere, for the frequency region of 10 to 300 GHz. Preceding the bibliographic presentation is an article-by-article synopsis of that literatu...

The Regional Administrative Radio Conference will be convened in 1983 for planning broadcasting-satellite service in the International Telecommunication Union Region 2 to resolve the issue of allocating orbital positions and radio frequencies in the ...

Pollard (1975) describes a "Monte Carlo" factoring algorithm based on iterating some specific quadratic polynomials. In this paper different polynomials are tested in the algorithm to see if a more efficient factoring can be obtained. The results are...

In the MF band, interfering signals from one or more broadcast stations can be received. During nighttime periods, this interference is caused by fading signals, propagated from distances of more than about 200 miles. It is the purpose of this report...

National and international work toward an Integrated Services Digital Network (ISDN) and the progress toward its implementation is described. Standards activity and technology relating to the ISDN, in the United States and abroad, are presented.

Privacy protection law in the U.S., May 1982

The ITS model of radio propagation for frequencies between 20 MHz and 20 GHz (the Longley- Rice model) is a general purpose model that can be applied to a large variety of engineering problems. The model, which is based on electromagnetic theory and ...

The possibility of an Integrated Services Digital Network (ISDN) encircling the globe by the year 2000 is of increasing interest to the worldwide telecommunication community—developers, carriers, manufacturers, and users. Accelerating telecommunicati...

This report summarizes techniques that use the measured instantaneous envelope statistics of arbitrary noise or interference processes to calculate the degradation these processes cause to digital communication systems. Computer implementation of the...

This report describes a laboratory experiment which was conducted to find out if the absolute attenuation of a 35 GHz signal by the molecular species H2O2 (hydrogen peroxide), HNO3 (nitric acid), NO2 (nitrogen dioxide), N2O (nitrous oxide) exceeds a ...

The geographic coverage of all telephone companies in the United States is presented in a series of maps depicting the operating areas served by Bell and each of the various independent telephone companies. Tables are also presented of state-by-state...

Satellite communications are likely to be used to provide thin–route telephone service in developing countries only if the cost of earth stations can be substantially reduced. A parametric analysis of earth–station design and service capabilities is ...

The Institute for Telecommunication Sciences has embarked upon a program to improve the techniques that are used to determine medium frequency broadcasting parameters. This work is motivated by the fact that increased transmitter power which is plann...

During the past several years, the Radio Spectrum Measurement System (RSMS) of the National Telecommunications and Information Administration (NTIA) has measured the emission spectra and other characteristics of many radars operating in the governmen...

In this report, the results of a study to improve the global maps of monthly median values of the F2 region critical frequency, foF2, using values determined from a theoretical model, are presented. The object of the study was to obtain values of the...

A model of the parameters that specify the structure of the electron density in the polar ionosphere has been developed. The model is based upon the modification of monthly median ionospheric parameters given by the CCIR by use of formulations that c...

Elevated Duct Data-Base Improvement, Dec. 1981

Starting from work by Furutsu, a multiple knife-edge attenuation function is derived. A series representation of the function is developed which is amenable to computer implementation. Comparisons of computer-generated numerical values with known res...

The purposes of this study (and subsequent efforts) are several: (1), to extend earlier models of the FM reception process, to include as much II "realism" – i.e., non-ideality of both the linear and nonlinear elements of the typical FM receiver – as...

The 1977 World Administrative Radio Conference for the Planning of the Broadcasting-Satellite Service decided that elliptical antenna beams should be used for satellite antennas for planning purposes. Since it is desirable to minimize the antenna bea...

Spectrum resource assessment in the 2300-2450 MHz band, Sep. 1981

Spectrum resource assessment in the 1660-1710 MHz band, Sep. 1981

The report is a study and primer of the discrete logarithm public key cryptographic system. Implementation and strengths and weaknesses are discussed.

Spectrum resource assessment in the 4400-4990 MHz band, Sep. 1981

Spectrum resource assessment in the 1215-1400 MHz band, Sep. 1981

This report presents the description, analysis and results of a set of measurements made on a 90 km line-of-sight path in Italy. The measurements were made during the late spring of 1980 by the National Telecommunications and Information Administrati...

Spectrum Resource Assessment in the 216-225 MHz Band, Sep. 1981

Several of the public-key cryptosystems that received considerable publicity are examined. The uses, implementation, and potential cryptoanalytic attacks are discussed. Since most of the suggested systems depend on the manipulation of large numbers, ...

This is a companion document to another NTIA Report, "Proposed Techniques for Adding FM Broadcast Stations in a Major Market." Increasing the number of assignments is possible if: 1) co–siting of second– and third–adjacent–channel transmitters is ...

The large amount of power contained in the main beam and principal sidelobes of the proposed Solar Power System (SPS), now under study by DOE and NASA, potentially presents an EMC problem for other satellite systems. This report examines selected geo...

The Department of Energy (DOE), along with the National Aeronautics and Space Administration (NASA), has been evaluating the Satellite Power System (SPS) as a source of baseline electrical power. The objective of the SPS program is to develop an init...

This report is the sum of a three–part effort by the Institute for Telecommunication Sciences (ITS) to provide technical recommendations for the DCS Long–Haul Tactical Common system, subsystem, and equipment technical standards for digital radio. The...

Final Report The NTIA rural communities field studies, April 1981

Trade Issues in Telecommunications and Information: Volume I. United States Trade in the Merchandise of Information Industries

Trade Issues in Telecommunications and Information: Volume II. The Employment Effects of Trade in High-Technology Telecommunications and Information Products

Trade Issues in Telecommunications and Information: Volume III. Promoting U.S. Trade in Telecommunications and Information Products with Developing Countries

Trade Issues in Telecommunications and Information: Volume IV. The Role of the United States Government in the Financing of Exports of Major Telecommunications and Information Products

Guidelines for interconnection to the United States Postal Service (USPS) Electronic Computer Originated Mail (E-COM) System via telecommunications carriers are developed. Adescription of the E-COM System is given and the need for telecommunications ...

Radio wave interaction measurements using the high power transmitter at Platteville have resulted in cross modulation of up to 30% as compared to the earlier cross modulation measurements of 7% or less at low power. A theory is derived which shows th...

The International Record Carriers have, for a number of years, provided a switched, overseas, voiceband data service called Datel. This report examines changes required in the Bell/Independent domestic MTS network to provide a more advanced form of i...

Throughout an area between Chicago and Peoria, Illinois, approximately 50 measurement locations were selected. At each location measurements were made, typically, for two VHF television broadcasts from Chicago and three UHF television broadcasts from...

This report categorizes the manner in which atmospheric stratification can complicate the problems of frequency allocation and radio regulation by inhibiting service fields and enhancing interference fields. For the United States and its border regio...

TOPOG is a computerized worldwide terrain elevation data base generation and retrieval system. It consists of software to generate TOPOG tapes from Defense Mapping Agency (DMA) standard terrain elevation data tapes, to create auxiliary random–access ...

This report describes the effort which will be undertaken to determine telecommunication standards necessary for interconnection to the United States Postal Service (USPS) planned long-range Electronic Mail Service System (EMSS). This work is in comp...

Interference to radio receivers, such as those used in radio astronomy, can present problems. Adding conventional filters to a radio astronomy receiver's input generally results in an appreciable increase in noise temperature if the filters have any ...

The solar power satellite (SPS) is a concept for generating electrical power from solar energy via a geosynchronous orbiting satellite. A facility, such as this, would be able to send approximately 5 to 10 gigawatts of power to earth on a highly focu...

The concept of collecting solar energy in an orbiting, geostationary, solar power satellite (SPS) and then beaming this power to earth via a focused microwave beam at 2.45 GHz has received considerable attention in recent years. This report examines ...

As with many technologies, the evolution of telecommunication systems is shaped by two driving forces – performance and cost. There is a real need to bridge the gap between 'performance' as perceived by the user in accomplishing a mission and 'perfor...

An automated, computer–controlled receiver system developed by ITS for the U.S. Army Communications Command provides a unique solution to such problems as spectrum management, EM hazards measurements, and site surveying. This receiving system is desi...

Thia report ia based on published cost figures of the TAT-6 submarine coaxial cable system which went into service on July 27, 1976. Assuming readiness of long wavelength (1300 nm) devices by the late 1980s, we project the expected cost of a fiber ca...

This report presents the results of mobile measurements of VHF signals in the Denver, Colorado, urban environment. The signals monitored were those received from the TV transmissions of KBTV (Channel 9), KMGH (Channel 7), KOA (Channel 4), and KWGN (C...

There is a growing need within the Federal government for a user-oriented, system-independent, functional means of specifying data communication performance. A recently published Federal Standard, Interim Federal Standard 1033, defines a set of stand...

Interference caused by local oscillator radiation from AM radios is a known problem. It is particularly troublesome when the local oscillator frequency of one radio coincides with the tuned frequency of another, nearby AM radio. This condition produc...

The FAA is currently developing the Discrete Address Beacon System (DABS) as an evolutionary upgrading of the Air Traffic Control Radar Beacon System (ATCRBS). Questions have been raised regarding the Electromagnetic Compatibility (EMC) of ATCRBS and...

Measurements of the amplitude probability distributions and the average crossing rates of the electromagnetic noise radiated by automotive ignition systems were made at 30 MHz, 47 MHz, 147 MHz, 224 MHz, and 445 MHz. The ignition noise from a single c...

A new, consumer–oriented family of innovative information distribution services, generically termed VIDEOTEX, is being offered to the European and Japanese public. Several field trials are underway in the U.S. Normally using a modified home TV receiv...

This report discusses microwave engineering data relevant to assess the potential of the Satellite Power System (SPS) to cause microwave field enhancements (so called "hot spots") inside habitable structures (house, trailer, car, etc.) located in the...

This report describes methods for calculating, under certain simplifying assumptions, footprints (contours of constant power density) for idealized models of several common types of transmitting antennas (circular aperture, elliptical aperture, recta...

The radio coverage for two maritime distress communication systems are calculated for those U.S. Coast Guard stations in the contiguous United States. The two systems are: the international MF distress channel and the international VHF distress chann...

This report describes the spectrum resource assessment of the 1710–1850 MHz band. The Phase I Report [Hurt and Crandall, 1980] provided information on frequency allocations, technical standards, spectrum usage, and identification of key spectrum mana...

Spectrum resource assessment in the 2200-2300 MHz band, Sep. 1980

A study was conducted to investigate the technical capacity of the FM broadcast spectrum and to determine if the FM spectrum's utilization could be increased. More assignments are possible if some or all of the following recommendations are adopted: ...

The radio wave propagation path between an earth station and a synchronous satellite 1s described by engineering-type formulas which consolidate all of the known external elements significant for system performance. This UHF/SHF consolidated model, a...

An experimental study of atmospheric multipath on a 23 km link at 9.6 and 28.8 GHz near Boulder, Colorado, is described. The preliminary observations were made for three days in July 1979 when a strong inversion layer was present, creating an elevate...

Middleton's analytical formula for the probability of communications in a land mobile environment and Berry's computer program for probabilistic calculations of interference are shown to produce identical answers for identical inputs. The assumptions...

The chronological development of the available methods for predicting medium frequency sky–wave strengths is presented with a brief discussion of each method. Measured field strengths for 36 medium frequency sky–wave paths are compared with the predi...

Measurements of the voice intelligibility over landmobile systems in the presence of vehicle noise are presented. These are compared with several statistical noise parameters obtained from measured amplitude probability distributions.

The pressure to provide additional full-time facilities in the AM (standard broadcasting) band in the United States resulted in a rulemaking petition filed with the Federal Communications Commission (FCC) by the National Telecommunications and Inform...

The communications network structures currently used to interconnect terminal clusters and switching nodes within an Army tactical command post and area signal center are reviewed. With this background, five alternative structures are defined in term...

This report summarizes the results of experiments undertaken to assess the potential impact of the operation of the Satellite Power System on the D and E regions of the ionosphere, and on telecommunication systems that are dependent upon the structur...

The National Telecommunications and Information Administration (NTIA) in the Department of Commerce undertook a detailed program to investigate the feasibility of deploying the Limited Surveillance Radars (LSR) in the 2.7-2.9 GHz band in the Los Ange...

Radio noise of ground-based origin can be observed by a satelliteborne receiver orbiting above the 2 region. The noise that is observed is a function of receiver frequency, satellite position, and local time at the sub-satellite point. A recently lau...

In military base access areas, akin to many commercial installations, the telecommunications traffic passes through several concentration and switching stages. Loads to server facilities are formed through mergers and branch outs of offered traffic s...

A study was conducted to determine the limiting propagation effects on the performance of a microwave system that could be used to detect the optical visibility between two vehicles, separated by up to 10 km, in irregular, obstructed terrain. The stu...

The United States Administration has proposed for the 1979 WARC (World Administrative Radio Conference) to move the BSS (broadcasting–satellite service) in ITU (International Telecommunication Union) Region 2 from the band 11.7-12.2 GHz to the band 1...

This paper discusses measurement of signals received over a 160-km (100-mile) line-of-sight microwave radio link operating at 8.4 GHz. Signals were recorded at both ends of the path at various times over a period of about 18 months. The effects of ma...

This report investigates the performance of an FM, landmobile, receiver in FM interference. Measurements are described showing the effects of multiple interfering FM signals as a function of modulation index, signal-to-interference ratio, signal-to-n...

The ability of a television receiving antenna to deliver adequate signal power to the terminals of its receiver is determined by its gain relative to a lossless half-wave dipole antenna. This report presents measured gain data for indoor television r...

The bit–error–probability performances of HF digital radio systems with respect to channel and equipment additive, multiplicative, and nonlinear distortions are evaluated with respect to the nine system design features that affect the performances. T...

This report describes instrumentation for fading studies and measurement results over an 88-km multiple-diversity line-of-sight microwave link across the English Channel operating in the 4 to 5 GHz frequency range. Signal level and fade, duration sta...

The capacity of a digital circuit switching system is defined in terms of its four major elements: the traffic offered by the interface element, the maximum traffic carried by the switch matrix, the maximum number of call attempts handled by the cont...

The possibility of overlaying a spread-spectrum system into frequency bands containing conventional FM land-mobile systems is examined. Overlaying here is interpreted as meaning the unrestricted operation of spread-spectrum and FM mobiles throughout ...

This report describes an experiment conducted over a LOS microwave link off the coast of southern California. The objective was to determine the effect of known anomalous propagating conditions, caused by persistent temperature inversions in the atmo...

The National Telecommunications and Information Administration (NTIA) in the Department of Commerce undertook a detailed program to investigate the signal processing properties of the primary radars in the 2.7 to 2.9 GHz band, and the Automated Radar...

Statistical methods are provided for estimating time and rate parameters of digital communication systems according to the specifications of the Proposed Federal Standard 1033. The methods may be applied to delay, disengagement, transfer and service ...

Relative gain of fifteen television receiving antennas was measured as a function of frequency and azimuth angle. Input voltage standing-wave ratio was measured as a function of frequency to determine the scalar impedance properties of the antennas. ...

An algorithm (PROGRAM WAGNER) that evaluates HF ground–wave attenuation over irregular, inhomogeneous terrain is used to compare calculated field strengths with observed measurements for 9 actual paths and frequencies ranging from 120 kHz to 50 MHz. ...

This report describes a desk-top computer system and mathematical models which were used in seven of its programs. These programs make key calculations in the design of line-of-sight microwave systems. The models have the following ranges; bit rates ...

This report summarizes activities associated with the Federal Government's program to assess the biological effects of nonionizing electromagnetic radiation being coordinated by the National Telecommunications and Information Administration (NTIA). I...

Strong electromagnetic (EM) energy sources up into the microwave range are examined and estimates are made of maximum EM field conditions to which automobiles could be exposed. The results are meant to alert automotive engineers to potentially hazard...

A software package of programs has been developed which automatically measures and analyzes the received signal level of four microwave communication receivers. The package will run on the Test and Acceptance Calculator Instrumentation which the USAF...

A number of factors, including network topology, traffic characteristics, switching technology, and transmission media, affect the choice of control signaling techniques to be used in networks of the future. In this report these factors are considere...

Conversion to digital transmission has renewed the concerns about what effects aircraft obstruction of microwave links have on user quality. This is of particular concern where it is necessary to install a telecommunication system that crosses runway...

The sole purpose of this publication is to provide the public with a list of existing computer aids for the evaluation of radio systems which operate in any part of the radio spectrum. Consequently, neither the Department of Commerce (DoC), nor t...

The use of spread-spectrum modulation in a common type of land-mobile radio service is studied. The radio service contains many networks operated independently, similar to the business land-mobile radio service. Network independence implies (among ot...

Measurements of radio propagation path loss and local ground conductivity were made over four paths in the 100 to 2000 kHz band. The paths were of lengths up to 50 km and were chosen to represent both extreme and typical topography and conductivity c...

The previously developed Rice-Holmberg (RR) rainrate model and the Dutton-Dougherty (DD) attenuation model for earth-space links, and their subsequent modifications, are reviewed. Predictions are compared with data observed both from the Communicatio...

Methods of determining the first-order parameters of both the approximate and exact Class A and B models are derived, for both the ideal case of infinite sample data the practical cases of finite data samples. It is shown that all (first order) param...

This report summarizes the characteristics of the U. S. public switched network and the maritime radio service, which impact the development of an Automated Maritime Mobile Telephone System (AMMTS). Features and performance parameters which appear de...

Known theory is applied to examine the channel transfer function for earth/space propagation paths through the atmosphere and over t he frequency range from 10 to 350 GHz. The associated attenuation and phase-delay characteristics are separated into ...

This report discusses the recent, current, and planned activities in domestic satellite communications in the United States. The present satellites in the domestic satellite service are discussed and the general technical characteristics are pres...

This report is the third in a continuing series devoted to the development of analytically tractable, statistical-physical models of man-made and natural electromagnetic interference. Here, the first-order statistical probability densities (PDFs) and...

This report describes the application of a high resolution (6 ns) pseudo-random noise (PN) channel probe for evaluating the transmission character of a land–mobile communication channel. Preliminary measurements were performed at a microwave frequenc...

The report examines the conditions under which spread–spectrum, land–mobile radio, and television can share spectrum. After a preliminary assessment, the report concludes that the interference caused by a constant amplitude, spread–spectrum system sh...

The combined effects of local interference, skywave ("skip") interference, and radio noise on Citizens Band radio range are calculated. If the ionosphere reflectivity is normal or above normal during the next solar cycle, and CB use does not decrease...

This report covers two key tasks of the Access Area Digital Switch (AADSS) program being conducted by NTIA/ITS for the U.S. Army Communications Systems Agency. First, a brief introduction to digital electronic private automatic branch exchanges (PAB...

A set of telecommunications performance parameters have been developed for proposed Federal Standard 1033. The measurement of five of these parameters, access time, incorrect access time, access denial probability, disengagement time and disengagemen...

There is a growing need within the Federal Government for uniform means of specifying and measuring the performance of data communication systems from the point of view of the digital services delivered to the end user. This report presents results o...

This volume presents three examples of the use of proposed Federal Standard 1033, "Digital Communication Performance Parameters," in specifying end-to-end telecommunication system performance. The examples illustrate, for the particular configuration...

This report reviews much of the earlier work on radio propagation in urban areas, including a good deal of data from measurement programs, careful studies of multipath propagation, and techniques to reduce multipath fading. A number of investigators ...

Approximate confidence limits for error rates (probabilities of an error) of digital communication systems are derived under the assumptions that the sample is large , the error rate is constant and the dependence between transmission s is governed b...

The report describes a simplified method of estimating the performance of coherent phase-shift keyed (CPSK) and noncoherent frequency-shift keyed systems (NCFSK) in interference. The method used is based on the eye diagram bound and provides an upper...

This report presents some estimates of the enhanced fields deduced from the presently available theory and observational data. The fields of interest are the enhanced fields that are encountered in the presence of the stratified atmosphere, the ducti...

A series of experimental measurements are described that examine the performance of the five different digital modems in Gaussian noise and additive interference. These experimental results are then compared with theoretical predictions to determine ...

This report summarizes the results of a number of studies of path-to-path, or location, variability of transmission loss at 20 MHz to 10 GHz. The studies show that such variability appears to be normally distributed and can, therefore, be represented...

Most man-made and natural electromagnetic interferences are highly non-gaussian random processes, whose degrading effects on system performance can be severe, particularly on most conventional systems, which are designed for optimal or near optimal p...

This report describes an initial computer program that produces statistical frequency-distance curves. The computer program has been developed as a tool for use by the frequency managers' community of OTP/IRAC. The statistical frequency-distance curv...

An approximate method for estimating the performance of digital systems operating with cochannel interference and Gaussian additive noise is described. The method uses Monte-Carlo techniques and an approximation, based on the geometrical characteriza...

This report describes an accurate, versatile FORTRAN computer program for tracing rays through an anisotropic medium whose index of refraction varies continuously in three dimensions. Although developed to calculate the propagation of radio waves in ...

The data from a large measurement program at VHF and UHF are carefully evaluated , summarized and compared with values predicted from models of radio propagation over irregular terrain. Particular problems of low antennas and the effects of vegetatio...

A method of bivariate interpolation and smooth surface fitting is developed for z values given at points irregularly distributed in the x-y plane. The interpolating function is a fifth-degree polynomial in x and y defined in each triangular cell whic...

Atmospheric radio wave propagation in the 40 to 140 GHz band is influenced by microwave spectra of oxygen (O2-MS) and water vapor. The report treats the complementary roles of controlled laboratory experiments and computer analysis for providing deta...

The effects of the atmosphere on radio propagation at frequencies of 10 GHz to 30 GHZ include attenuation and depolarization by precipitation, absorption by water vapor and oxygen, and multipath fading related to refractivity gradients in stratified ...

This report is a study of the feasibility of applying numerical mapping techniques to the storage and handling of OMEGA propagation corrections. Using the techniques discussed in the report, it is possible to represent the 110,592 propagation corecti...

References are presented on the subject of recent (1971 to mid-1974) work on radio propagation through the atmosphere at frequencies from 10 to 100 GHz. The references are separated into six major categories covering propagation through precipitati...

Historically, multipath problems have been handled on an ad hoc basis requiring liberal portions of hindsight, engineering ingenuity and serendipity. However, as is often the case, once the underlying principles are identified, theoretical developmen...

The Office of Telecommunications, Institute for Telecommunication Sciences (OT/ITS), over the past several years, has accumulated a data base of man-made radio noise measurements in the frequency range from 250 kHz through 250 MHz taken in a number o...

A general statistical-physical model of man-made radio noise processes appearing in the input stages of a typical receiver is described analytically. The first-order statistics of the se random processes are developed in detail for narrow-band recept...

A generally accepted spectrum use metric (unit of spectrum-space use) would expedite efficient allocation and management of the spectrum resource. It would be useful for quantitative studies of spectrum congestion, and for economic analysis of the re...

It is well known that the amplitude-probability distribution (APD) function of atmospheric radio noise can be closely represented by a curve that one can select from a family of curves by specifying the ratio of rms to average voltage, usually expres...

A bibliography is presented on the subject of electromagnetic wave propagation over line-of-sight paths through the troposphere at frequencies above 10 GHz. The references are divided into three main categories covering the areas of propagation throu...

The correlation of the man-made radio noise envelope voltage from two receiving systems was measured as a function of the antenna configuration of the systems. Combinations of vertical omnidirectional antennas and half-wave dipole antennas in corner...

An analysis is presented of air-ground radio wave propagation measurements, which were performed using an airborne transmission source at approximately 6,400 m above msl. Receiving antennas were slightly within and beyond line-of-sight of the airborn...

Telecommunication technology and its applications are rapidly expanding in the new or developing nations, many of which are located in tropical climates; so a knowledge of the behavior of refractivity gradients, directly related to establishing and m...

This report summarizes measurements of tropospheric transmission loss and its long-term variability for nearly 800 paths in various parts of the world. The measurements were made at frequencies from 40 MHz to 10 GHz over distances which range from 10...

This is the fourth part of a four-part report containing tabulations and graphs of transmission loss data resulting from propagation experiments in the 230 - to 9200-MHz frequency range conducted over irregular terrain in Colorado. This part presents...

During May and June of 1968, OT/ITS conducted a man-made radio noise survey of San Antonio, Texas. The results of part of this survey of residential urban man-made radio noise are given, along with the correlations of the measured values of noise pow...

Several examples of the numerical evaluation of an integral equation for the calculation of the attenuation of a radio wave are given. These waves are assumed to be propagated over realistic, smoothly varying irregular, inhomogeneous terrain. Results...

Worldwide atmospheric noise at 1 MHz, as presented in CCIR Report 3 22 (1963), has been numerically mapped in universal time. The mapping technique and representative contour maps for January and July, are presented. Fourier analyses were performed s...

This is the third part of a four–part report containing tabulations and graphs of transmission loss data resulting from propagation experiments in the 230- to 9200- MHz frequency range conducted over irregular terrain in Colorado. This part describes...

Predictions of tropospheric transmission loss over irregular terrain using the computer methods described by Longley and Rice (1968) are compared with measurements, to determine their limits of applicability and define the boundary conditions for the...

This report is a presentation in two volumes of measurement techniques, data, comparisons, and conclusions obtained from a UHF propagation measurement program at 230 and 415.9 MHz. Antenna heights were 3 m or less above ground. Vertical polarization ...

This report is a presentation in two volumes of measurement techniques, data, comparisons, and conclusions obtained from a UHF propagation measurement program at 230 and 415.9 MHz. Antenna heights were 3 m or less above ground. Vertical polarization ...

Desired-to-undesired signal ratio predictions for the VHF Omnirange (VOR) and Instrument Landing System (ILS) air navigation aids are presented. The parameters involved in these systems are given first. Propagation mechanisms applicable to VHF /UHF a...

The report describes a series of computer routines for analyzing HF radio propagation in an arbitrary ionosphere - in particular, the echoes obtained in ionospherically propagated ground backscatter experiments. With the aid of a plotting routine t...

A numerical method for calculating the scattering and diffraction at an antenna site to be used in a sky-wave communication link is derived. The method of physical optics is used to treat the scattering by the terrain surrounding the antenna site. ...

This is the second part of a four-part report containing tabulations and graphs of transmission loss data resulting from propagation experiments in the 230 to 9200 MHz frequency range conducted over irregular terrain in Colorado. This part describes ...

This report describes a computer method for predicting long-term median transmission loss over irregular terrain. The method is applicable for radio frequencies above 20 MHz and may be used either with detailed terrain profiles for actual paths or wi...

This four-part report contains tabulations and graphs of transmission loss data resulting from propagation experiments in the 230 to 9200 MHz range conducted over irregular terrain in Colorado. Each part of the report deals with data obtained at a si...

After a brief description of the significance of the radio refractive index and its variation in the lower troposphere, a catalog of fading mechanisms is presented. Attention is directed to the supporting refractive index structure, the characteristi...

This report contains tabulations of transmission loss data resulting from propagation experiments at 20, 50, and 100 MHz conducted over irregular and partly wooded terrain in northeastern Ohio. Raw data from measurements described in this report is a...

After a brief description of the significance of the radio refractive index and its variation in the atmosphere, a brief catalogue of fading mechanisms is presented. Attention is directed to the variety of fading mechanisms that are pertinent for th...

This report contains tabulations of transmission loss data resulting from propagation experiments at 20, 50, and 100 MHz conducted over irregular terrain in the Colorado Mountains primarily east of the Continental Divide.Raw data from measurements de...

This report contains tabulations of transmission loss data resulting from propagation experiments at 20, 50, and 100 MHz conducted over irregular terrain in the Colorado high plains east of the Continental Divide.Raw data from measurements described ...

Desired-to-undesired signal ratio predictions for the VHF Omnirange (VOR), Tactical Air Navigation (TACAN) and Instrument Landing Systems (ILS) air navigation aids are presented in this report. The parameters involved in the various systems are given...

Vertical radiation patterns of vertical quarter-wave monopoles, and of vertical and horizontal half-wave dipoles located at various heights up to twenty wavelengths over several typical types of ground are shown. Vertical antennas have the best low-...

Geographic and frequency dependent distributions of atmospheric noise power enumerated in CCIR Report 322 [1964] are approximated by series expansions for use in electronic computers. Coefficients of Fourier series representation of worldwide geograp...

The proposed experiments described in this report are designed to obtain information concerning the feasibility of tropospheric scatter transmission between an earth terminal and a satellite. These experiments are suggested in lieu of experiments ut...

A comparison is made at X-band frequencies of the theoretical and measured transmission and reflection coefficients for a parallel wire grid. The methods used are applicable to the measurement of these factors for various building materials.

Results of measurements of basin transmission loss over 400 and 600 miles paths are presented in the form of distributions of hourly medians for frequencies in the 100 to 1000 Mc range. The paths extend southeastward from the Front Range of the Colo...

A solution is presented in this paper, with all of the variable subject to error, for the general leased squares porblem of determining consistent estimates of the parameters of a functional relationship which is expected to fit exactly the average o...

A solution is given for fields of a circular loop in a conducting medium. The loop is assumed to have a uniform current and it is enclosed by a spherical insulating cavity. The impedance of the loop is also considered. It is shown that the power ...

A different author or authors wrote each section of this report or its appendices. Volume II is Appendices.

A brief survey is given of results from an experimental program extending over the last five years to investigate the nature and characteristics of high-loss regular VHF propagation by means of scatteriung and other mechanisms in the lower ionosphere...

Initial results through December 1954 are reported from a continuing investigation of the extreme distance range of regular VHF propagation by scattering in the lower ionosphere. Signal strength observed at 36/Mc/s over an experimental path from New...

This report describes tropospheric propagation measurements taken over the Cheyenne Mountain paths on frequencies between 92 and 1046 Mc during February, 1954. The results of the measurements are given in terms of cumulative distributions of hourly ...

A description is given of the facilities provided by the National Bureau of Standards on Cheyenne Mountain in Colorado and in its vicinity which are used for the measurement of the transmission loss on radio transmission circuits operated in the freq...

In this paper there is derived an approximate formulation of the problem of a scalar wave propagated over an irregular bounding surface. This formulation takes the form of a one-dimensional Volterra integral equation, which can, or so it appears, be...

Basic Radio Propagation Predictions are prepared by the staff of the Central Radio Propagation Laboratory of the National Bureau of Standards under the direction of J. Howard Dellinger, Chief, and Newbern Smith, Assistant Chief. The monthly reports o...

This memorandum provides technical details for the image quality experiment COCRID: A Challenging Optical Character Recognition Dataset. The design goals of the COCRID dataset are (1) to train no-reference metrics that track the quality of recognized...

Today’s mobile wireless networks comprise many proprietary solutions with custom, closed-source software and hardware. Changes to these proprietary elements require complex and meticulous verification of the entire network. This dynamic increases cos...

This study examines the effects of resolution bandwidth (RBW) when using the measurement methods described in National Telecommunications and Information Administration (NTIA) Technical Report 05-420 to measure the emission spectra of compound radar ...

The Gilbert-Elliot model is a popular and effective tool for treating bursty (nonindependent) errors in communication links. This memorandum provides linkages between model parameters and error statistics. The motivation is that these linkages can al...

This memorandum provides technical details of the VCRDCI dataset. This dataset was designed similarly to a video quality subjective experiment, but the VMAF metric was used to create simulated subjective data. The VCRDCI dataset contains 130 scenes t...

This technical memorandum provides details for the image quality subjective experiment ITSnoise. This experiment includes 24 scenes, each digitally photographed using 12 different Image Capture Methods (ICMs) for a total of 288 images. The ICMs were ...

This technical memorandum describes a method to design, characterize and optimize a system for performing field measurements of aggregate interference from LTE user equipment transmissions. It explains the computation of the system’s antenna gain ove...

This technical memorandum provides the results of a compatibility assessment between terrestrial GPS L1 coarse/acquisition (C/A) code receivers operating in the 1559-1610 MHz RNSS band and terrestrial operations in the 1526-1536 MHz, 1627.5 1637.5 MH...

This paper analyzes the performance of eight no-reference (NR) metrics. Seven assess image quality (BRISQUE, CurveletQA, IL-NIQE, NIQE, OG-IQA, QAC and SSEQ) and one assesses video quality (VIIDEO). The challenge we address in this paper is moving fr...

This technical memorandum provides technical details for the video quality subjective experiment its4s4. This experiment includes 196 videos, each 4 seconds in duration, depicting camera pans at different speeds. Other impairments are avoided where p...

This technical memorandum provides technical details for the video quality subjective experiment its4s3. This experiment includes 594 videos, each 4 seconds in duration. The experiment consists of six sessions, each portraying a different public safe...

This technical memorandum provides technical details for the image quality subjective experiment its4s2. This experiment contains 1,473 still images that were presented to subjects for 4 seconds each, as per still video. The goals are (1) to train no...

In support of the Network Universal Persistence (Network UP) Broad Agency Announcement (BAA) sponsored by the Defense Advanced Research Projects Agency (DARPA), the Institute for Telecommunication Sciences (ITS) was asked to perform a dual-band tacti...

This report describes a set of best practices for the preparation and verification of radio propagation measurement systems. We discuss advantages and disadvantages of various channel sounders, the common components used in these systems, and measure...

NTIA Technical Memorandum TM-18-527 describes procedures for testing the functionality of Environmental Sensing Capability (ESC) sensors that will detect 3.5 GHz radar signals for future spectrum sharing systems. The present document describes addit...

This report describes the video quality subjective test its4s, including the experiment design and footage attribution. Subjective experiment its4s includes 813 unique video sequences, each four seconds in duration. No video sequences are repeated. T...

This paper describes the design and retrofit of the 3.7 meter (12-foot) dish antenna located near building I10C at the U.S. Department of Commerce Table Mountain Field Site and Radio Quiet Zone.

A planned procedure is described for testing 3.5 GHz environmental sensing capability (ESC) devices for their responses to radar pulses in a laboratory environment. These test procedures will be used to gather data on ESC pulse-detection performance....

Future 3.5 GHz Citizens Broadband Radio Service Device (CBSD) transmitters in the U.S. will share spectrum with incumbent Federal radar systems. To avoid interfering with radar receivers in exclusion zones, CBSDs will be deployed in conjunction with ...

This report identifies camera technology gaps that impact first responders. These technology gaps were identified by interviewing first responders about images, video, and camera systems in general. This is a working document that is intended to fost...

Crowdsourcing of subjective speech, audio, and video quality of experience (QoE) tests has received much interest and study, but crowdsourcing of speech intelligibility testing has not. We hypothesize that speech intelligibility tests offer a unique ...

This report provides full technical details for the video quality subjective test AGH/NTIA. Analyses of this dataset appear in separate publications. The purpose of this document is to provide design details that are beyond the scope of a conference ...

This memorandum describes the Fast Low Bandwidth model. This summary is intended to help the reader understand the model from an algorithmic standpoint. Some knowledge of prior NTIA objective video quality models is necessary for the understanding of...

This Technical Memorandum describes a process for selecting an appropriate antenna for monitoring radio signals from airborne transmitters. A mathematical formula for the optimal receiver antenna gain is presented. This formula takes into account the...

This memorandum contains two compilations of antenna parameters. The first one is the collection of rules, regulations, and recommendations regarding antennas that are published by authoritative institutions such as NTIAthe FCC, International Telecom...

Time varying delays of the output (or processed) video frames with respect to the input (i.e., the original or reference) video frames present significant challenges for Full Reference (FR) video quality measurement systems. Time alignment errors bet...

Wireless communications experience temporal variations in received signal level that are characteristic of the propagation channel. Propagation channel fading at VHF and above is predominantly caused by the complex scattering environment through whic...

Digital video transmission systems consisting of a video encoder, a digital transmission method (e.g., Internet Protocol—IP), and a video decoder can produce pauses in the video presentation, after which the video may continue with or without skippin...

The quality perception of an audiovisual sequence is heavily influenced by the quality of the audio, the quality of the video, and the audiovisual time synchronization. The questions then arise: what is the relative importance of each factor, and can...

NTIA/ITS has conducted a series of studies to quantify the effects that individual audio and video qualities have on the overall Mean Opinion Score (MOS) for a given set of audiovisual clips. The experiment described in this report studies the effect...

This NTIA Technical Memorandum provides a single, comprehensive set of derivations of the mathematical relationships among power in a radio transmitter or measurement circuit, the associated incident field strength in space, transmitter-receiver ante...

This technical memorandum examines issues related to the potential interference impact of a specific Cellular Radiotelephone Service (Cellular) and Personal Communications Service (PCS) jammer transmitter on selected out-of-band and in-band receivers...

The National Telecommunications and Information Administration (NTIA) is developing a handbook documenting the best practices in spectrum engineering. This technical memorandum provides a methodology to determine the average and peak power level at t...

ITS is conducting a series of studies to quantify the effects of the separate audio and video compression qualities, and the differential delay in their synchronization, to the perceived aesthetic quality of a multimedia signal. The experiment descri...

Digital video transmission systems consisting of a video encoder, a digital transmission method (e.g., Internet Protocol – IP), and a video decoder can produce pauses in the video presentation, after which the video may continue with or without skipp...

In 1997, the Federal Communications Commission (FCC) authorized the use of Unlicensed National Information Infrastructure (U-NII) devices in the 5150–5250 MHz, 5250–5350 MHz, and 5725–5825 MHz bands. The technical and operational requirements are dif...

Digital video transmission systems consisting of a video encoder, a digital transmission method (e.g., Internet Protocol – IP), and a video decoder can produce pauses in the video presentation that result from dropped or repeated video frames. For ex...

This report presents four sets of equations developed by the National Telecommunications and Information Administration (NTIA) Office of Spectrum Management (OSM) to compute the bandwidth correction factor (BWCF) for peak and average power levels and...

In response to interference from an S–band (2700–2900 MHz) airport surveillance radar (ASR) to a meteorological (weather) radar in the same band, measurements were performed at the field location of the two radars to determine the interference mechan...

This technical memorandum describes the results of radiated measurements of the emission spectrum of a maritime radar at varying azimuths relative to the base of the radar transmitter antenna rotary joint. The measurements were performed to address t...

This technical memorandum describes measurements of the radiated emission spectra of selected maritime radiolocation radar transmitters in multiple bandwidths. The results support published criteria for selection of measurement bandwidths for emissio...

The effects of mutual coupling on the radiation pattern of a four–element linear array were investigated. The objective was to improve the angular resolution of the array for direction–of–arrival estimation by compensating for mutual coupling. It is ...

It has been proposed that first–order Markov channel models can be used to adequately predict the behavior of a mobile "Rayleigh" fading channel and hence improve the reliability of bidirectional mobile communications systems. Previous authors have a...

Digital video compression algorithms are being deployed that spatially stretch or shrink the video picture. Although small changes in spatial scaling are not usually noticeable to viewers, objective video quality measurement systems may be adversely ...

This memorandum compares subjective video quality test results from a professional cathode ray tube (CRT) television monitor with that of a consumer liquid crystal display (LCD) video phone monitor. The CRT monitor supported the full ITU–R Recommenda...

This document discusses a method for correcting inaccurate color output by digital still and video imaging systems. The method uses a known reference image together with a least–squares algorithm to estimate the optimal color channel mixing matrix th...

A particular concern about digital television (DTV) broadcasts is whether such broadcasts have sufficient power to be received using inexpensive indoor antennas located inside a typical home. To test this, the Institute for Telecommunication Sciences...

A multiple data set fitting problem often arises in conjunction with the development of objective estimators of perceived audio or video quality. In such development work, we often seek the best linear relationship between a set of objective audio or...

It is often desirable to compensate for system gain, especially before objectively estimating perceived audio or video quality from system inputs and outputs. A common approach is to scale the system output to compensate for system gain. One can take...

This report assesses the expansion of the Earth Exploration-Satellite Service in the 8025–8400 MHz frequency range. The report identifies allocations, standards, regulations and current and planned spectrum usage applicable to this range for Governme...

Automatic Link Establishment (ALE) technology automates the selection of channels and establishment of links among high-frequency radios, but creates a vulnerability in such automated networks to hostile manipulation of network operations. The Linkin...

Automatic Link Establishment (ALE) technology automates the selection of channels and establishment of links among high-frequency (HF) radios. This report describes software that simulates fading channels and the Federal Standard ALE modem used over ...

The National Land Mobile Spectrum Requirements report was released in January 1994. This report describes the Federal Government's land mobile radio (LMR) usage and trends in the following bands: 30–50, 138–150.8, 162–174, 220–222 and 406.1–420 MHz. ...

Automatic Link Establishment (ALE) technology automates the selection of channels and establishment of links among high-frequencyradios, but creates a vulnerability in such automated networks to hostile manipulation of network operations. The Linking...

A user's guide and programmer's reference manual is presented to facilitate the use of two high frequency circuit analysis software systems called VOACAP and REC533. The guide shows how to execute the software on laptop computers and personal compute...

In this technical report, preliminary graphical models spanning approximately 1 MHz to 30 GHz are developed for commercial and residential building attenuation. The models are least-square fits to the data available from the open literature. An estim...

This report provides a feasibility assessment of accommodating the Broadcast Satellite (Sound) Service and a Mobile Satellite Service uplink in the 2300–2450 MHz range. The assessment is based upon measurements by the Institute for Telecommunication ...

A program plan and its rationale are presented to determine estimates of the resources needed to test existing high-frequency (HF) broadcast receivers and to develop a single-sideband (SSB) HF broadcast "low-cost" prototype receiver. The plan include...

In light of the decisions made by the Administrative Council of the International Telecommunications Union to postpone the high-frequency (HF) broadcast conference scheduled for 1993 the Institute for Telecommunication Sciences documents its improved...

This report includes NTIA measurements of characteristics of nonlicensed devices. These devices are authorized under the FCC Rules in CFR 47, Part 15. The measured values are intended for use by the Government in analysis of potential interference be...

A fully automated version of a model to predict relative received powers and bit error rates from microwave common carrier transmissions between e and er GHz is developed. Earlier computer programs that were not fully automated are discussed in the s...

The geostationary Satellite Orbit Analysis Program (GSOAP) analyzes system performance and mutual interference of communication satellites using the geostationary satellite orbit. This manuwal presents information necessary to the user of GSOAP, Vers...

This technical report details a procedure for calculating the mainbeam off-axis power density in the near- and far-field of a parabolic circular reflector antenna. In the report, the on-axis procedures of an earlier report are extended to off-axis an...

This report describes analysis models and software packages developed by the National Telecommunications and Information Administration (NTIA) for the assessment of single-entry and aggregate interference from terrestrial emitters into terrestrial or...

[to be added]

This report documents a spectrum resource assessment of the bands allocated to the Federal Government fixed service above 400 MHz on a primary basis. The assessment identifies allocations, standards, channeling plans and technological trends pertaini...

This report discusses simplified procedures for calculating near and far field intensities of several types of aperture and wire antennas. The antenna technical characteristics listed in the Government Master File (GMF) were reviewed. For this analy...

This report is a study of the potential for sharing in the 4500–4800 MHz band between the fixed-satellite service (FSS) and terrestrial (fixed and mobile) services. The report focuses on decisions of the WARC-ORB-85 concerning planning of the FSS in ...

This report documents the NTIA Task Force visit to the Naval Air Test Center (NATC), Patuxent River, MD, from January 13 through February 12, 1986, in response to a request from NATC, the Mid-Atlantic Area Frequency Coordinator, and the Navy Interdep...

This report documents an effort to measure the operational and performance characteristics of radios equipped with the Data Encryption Standard (DES), as applied to government land-mobile operations.

Before 1987 no commercial trunking systems were available in any Govenment or non-Government band below 800 MHz. This study examines the application of trunking to the Government band 406–420 MHz. As a result of this study and subsequent discussions ...

This report presents a bibliography, categorized by region, of some recent work on the high-latitude ionosphere. It contains a brief introduction to the characteristics of the ionosphere at high latitudes, and a synopsis of a few articles. The appr...

The possibility of allowing shipborne navigation radars within the 9300–9320 MHz band is being considered within Study Group 8 of the International Radio Consultative Committee (CCIR) and within the United States preparation for the 1987 Mobile World...

The Technical Spectrum Efficiency Factor (TSEF) concept was developed in the Technical Subcommittee (TSC) of the Interdepartment Radio Advisory Committee (IRAC) and was applied, by NTIA, to government fixed telecommunications systems in the 7–8 GHz b...

This evaluation consisted of an on-site visit to the Ministerio de Transporte y Comunicaciones (MTC) in Venezuela in November 1984 and subsequent discussion between the representatives of the MTC and National Telecommunications and Information Admini...

This report evaluates the spectrum management structure in Papua New Guinea (PNG) and recommends methods to improve spectrum management procedures and computer-aided techniques used by PNG. This evaluation consisted of an on-site visit to the Post a...

This is the final report on work performed at the Institute for Telecommunication Sciences on “Atmospheric Transfer and Shielding Properties in the 50 to 75 GHz Band” (ARO Proposal NR. 12233 GS). The microwave spectrum of oxygen (02—MS ) was in...

A 64 km path between the islands of Hawaiʻi and Maui was measured using a Geodimeter with refractive index correction based on airborne measurements of temperature along the line. The standard deviation of the slant range is estimaged as about 0.9 p...

A theoretical expression for the received signal by a radar is reduced to a utilitarian form by the introduction of feasible approximations and assumptions, with concern expressed for the need for evaluation of errors caused by these approximations...

This report summarizes non-government use of Land Mobile Radio. The services provided by LMR are described and the spectrum allocations are outlined. A brief discussion of the present overcrowding of the LMR bands is given along with suggestions that...

Digital data transmission tests using a 12.6 Mb/s data stream (3-level partial response) were performed over a l16-kmline­of-sight link in northeastern Colorado using a carrier fre­quency in the 11.2 -11.45 GHz band. During the first four days of a f...

The extended offshore test range proposed for the Pacific Missile Range will use high altitude aircraft to relay signals for tracking, telemetry, and control. This report treats the reliability of the radio propagation paths between these relays and ...

A theoretical expression for the received signal by a radar is reduced to a utilitarian form by the introduction of feasible first order approximations, and specifying where other common assumptions are made, with concern expressed for the need for e...

Following the alignment and tuning of an analog FM microwave radio to handle a 12.6 Mb/s, 3-level partial response base­band, the effects of various types of interference on system performance were investigated. Since TDM-FM and FDM-FM microwave syst...

A computer procedure called program AREAPOP is used to count the number of persons and housing units within Grade A and Grade B service contours of 294 Public Broadcasting Service television stations in the United States. These population statistics ...

This memorandum is concerned with scintillation effects on digital multiple phase shift keying (MPSK) channels in presence of additive Gaussian noise. The basic channel statistics, such as the correlation bandwidth and related spreads, are introduce...

The Born approximation is used to derive a general expression for a radio wave passing through a random medium. The medium is characterized by a random index of refraction. An explicit transfer function is derived using the Fremouw and Rino model for...

This report considers the minimum bit-rate required for trans­mission of NTSC video color standard when used for tele­conferencing. The smallest values are found for fixed cameras. The use of split screen images will increase the required bit­rate by...

Estimates for the effects on a lateral wave of a clearing in a foliage layer are considered. A first-order solution to the integral equation for the mixed-path problem is derived and two examples are considered. They show that a m.id-path clearing ha...

This study concerns ionospheric scintillation as it affects satellite communications between about 100 MHz and 30 GHz. It is divided into three parts. The first part reviews the pertinent physics and suggests some boundaries and values for some of th...

An analog FM microwave radio was tuned and tested to published specifications. Appropriate interface changes were determined and made to permit this radio to handle a 12.6 Mb/s 3-level partial response digital baseband. Pilot, orderwire, and combiner...

HF radio propagation predictions are calculated for Voice of America circuits using the OT/ITS prediction program. Some of the parameter s given are maximum usable frequency (MUF), the optimum traffic fre­quency (FOT), the lowest useful frequency (LU...

Due to seasonal variations of thunderstorm activity, and owing to the nonstationary conditions of atmospheric radio noise, it generally is not feasible to conduct performance tests of radio communications systems during periods of actual thunderstorm...

VOLUME I: HF radio propagation predictions are calculated for Voice of America circuits using the OT/ITS prediction program. Some of the parameters given are maximum usable frequency, the optimum traffic frequency, the lowest useful frequency, availa...

A study of the HF propagation using SSB voice communications for the U.S. Coast Guard's Automated Merchant Vessel Reporting (AMVER), voluntary weather observations n1.ETEO), and search and rescue (SAR) is presented in this paper. Charts of the Atlant...

This report contains a summary of work performed for the United States Information Agency, Voice of America, under contract IA-16744-23 for the period July 1973 through June 1974.

We consider a wideband detection problem where the number and struc­ture of the received signal set is arbitrary. A particular spectral weighting approach is taken and the processing results are found to be inadequate. The search for substantially be...

The radiation fields (i. e., elevation patterns) of HF coastal antennas are computed for several possible terrain profiles near land-sea bound­aries. The numerical technique for evaluating the radiation fields is compared with analytical formulas if ...

This report reviews the available documentation for two links of the FACSFAC microwave system and the findings of on-site inspections. It is recommended that the present maintenance program be supplemented by additional performance monitoring. This s...

HF radio propagation predictions are calculated for 35 circuits from the Voice of America transmitting facility at Tinang, P. I. and 30 circuits from their facility at Kava1a, Greece, using the OT/ITS prediction program. The program selects the optim...

The Institute for Telecommunication Sciences provided technical assistance to the Maritime Administration in the development of a digital selective calling system for use by the maritime mobile service. This report summarizes the work performed on th...

The potential interference between systems in the 1535-1660 MHz bands was investigated. This investigation shows that all intersystem inter­actions could be placed in Serious, Manageable or No Problem categories. The single serious problem results fr...

This user's manual contains a program description of what the "WARC 71.A29" does, a sample calculation, explanations, and instructions for use of the program. Guidance is provided as to the various sources of information needed to operate the program...

The Pacific Basin AMVER communications system was examined over extremes of ionospheric and noise parameters. An analysis was made of the station-frequency pairs available for communicating to 286 simu­lated ship positions in the area and recommendat...

HF radio propagation predictions are calculated for 35 circuits from the Voice of America transmitting facility at Tinang, P. I. and 30 circuits from their facility at Kavala, Greece, using the OT/ITS prediction program. The program selects the optim...

HF radio propagation predictions are calculated for Voice of America circuits using the OT/ITS prediction program. Some of the parameters given are maximum usable frequency, the optimum traffic frequency, the lowest useful frequency, available signal...

HF radio propagation predictions are calculated for Voice of America circuits using the OT/ITS prediction program. Some of the parameters given are maximum usable frequency, the optimum traffic frequency, the lowest useful frequency, available signal...

HF radio propagation predictions are calculated for 35 circuits from the Voice of America transmitting facility at Tinang, P. I. and 30 circuits from their facility at Kava1a, Greece, using the OT/ITS prediction program. The program selects the optim...

VOLUME I: HF radio propagation predictions are calculated for Voice of America circuits using the OT/ITS prediction program. Some of the parameters given are maximum usable frequency, the optimum traffic frequency, the lowest useful frequency, availa...

This report contains a summary of work performed for the United States Information Agency, Voice of America, under contract IA-16129-23 for the period July 1972 through June 1973.

A computer procedure is described which provides a map of population and/ or housing units. Another procedure finds the population within arbi­trary circles. The data base is the 1970 Master Enumeration District List, with coordinates, furnished by t...

HF radio propagation predictions are calculated for Voice of America circuits using the OT/ITS prediction program. Some of the parameters given are maximum usable frequency (MUF), the optimum traffic fre­quency (FOT), the lowest useful frequency (LUF...

M. F. broadcasting from. so-called "pirate" radio stations has plagued many of the advanced countries of the world. With the final disposition of the WXUR case in June 1973, Dr. Carl McIntire appears to be making good his proposal to resume broadcast...

HF radio propagation predictions are calculated for Voice of America circuits using the OT/ITS prediction program. Some of the parameters given are maximum usable frequency (MUF), the· optimum traffic fre­quency (FOT), the lowest useful frequency (LU...

HF radio propagation predictions are calculated for circuits from the Voice of America transmitting facility at Tinang, P. I. and 25 circuits from their facility at Kavala, Greece, using the OT/ITS prediction pro­gram. The program selects the optimum...

A novel, five-wire, rhomboid-shaped Beverage developed at Rome Air Development Center, Griffiss AFB, is examined from the standpoint of its applicability to HF, over-the-horizon radar. Both receiving and transmitting applications are considered. The ...

HF radio propagation predictions are calculated for 35 circuits from the Voice of America transmitting facility at Tinang, p. I. and 30 circuits from their facility at Kavala, Greece, using the OT/ITS prediction pro­gram. The program selects the opti...

Program LOSS was designed to compute estimated statistics of the path loss between two radio antennas operating at frequencies between 20 MHz and 20 GHz. It was written specifically for the CDC 3000 and 6000 series of computers. This "User’s Gu...

A binary code that satisfies requirements for the Decision Information Distribution System (DIDS) is generated. Requirements for the code, procedure for generating such a code, and resulting code are described. Comparison with the theoretical bounds ...

This report tabulate s population data for the area surrounding 322 selected radio and television stations in the continental United States. Specifically, the population within 10, 20, 30, 40, 50, 60, and 70 miles is estimated. Associated rankings an...

A fixed-beam, bistatic CW experiment designed to measure the temporal statistics of the volume reflectivity produced by hydrometeors at several selected altitudes, scattering angles and at two frequencies (3. 6 and 7. 8 GHz) is described. Surface rai...

The determination of an optimum receiving system for a given class of signals or how satisfactorily a given receiving system will operate requires information on the interference environment in which the system must operate. The important interferenc...

The subject computer programs are described and the FORTRAN source decks are Listed. The physical problem solved by the computer program is described. It allows an anisotropic ionospheric model, and variations in the model along the propagation path....

A computer based simulation model (Hatfield and Adams, 1970) was used to analyze the coverage obtained in the Command and Control and Arctic areas when transmitting CW and FAX from the U. S. Coast Guard's Otis AFB, Cape Cod, Massachusetts facility. T...

The three sites selected by USCS as a result of Part 1 have been simulated in combination with the seven existing radio stations. The HF (4-22 MHz) predicted performance for all such combinations has been computed for the worst case propagation condi...

This report supplements information previously developed by the authors on interference predictions for VHF/UHF air navigation aids, Included are (a) radiation patterns needed to adapt curves previously developed for the Instrument Landing System (IL...

Some factors which could or should affect frequency allocations and assignments in the future are considered. These include propagation predictions, modulation, coding and information processing. In addition a forecast of the use of cables as replace...

The critically increasing demand for radio frequency allocations has stimulated development of information needed to reexamine efficient use of the radio spectrum. The characteristics and limitations, of the radio channel, with emphasis on the transm...

During the Engineering Experimental Phase (1971-73) of the National Data Buoy Development Project, the U. S. Coast Guard (USCG) will deploy a network of automatic buoys in the Gulf of Mexico. They will gather oceanographic and meteorological data tha...

Azimuth and spectrum spread was measured from sidescatter and great circle signals over two transmission paths: Washington, D. C. to Boulder, Colorado, and Long Branch, Illinois, to Boulder. Both Doppler and fading spread were measured. The effective...

An ideal dispersion filter for simulating ionospheric dispersion is defined as one with constant dispersion in a channel frequency band and zero dispersion outside the band. An optimum lumped-element all-pass filter that approximates this ideal has a...

Published measured profiles of the lower ionosphere are used as the basis of an analytic model of the D-region electron density which varies with the sun’s zenith angle. The model is the sum of an exponential layer and a daytime Chapman-like C-layer....

Tests of the radiation efficiency of a dipole antenna 100 ft. long and buried in Sherman granite are described. The measurements were taken under winter conditions as a comparison with earlier measure­ments made in summertime; this determines whether...

Typical amplitude and time statistics of atmospheric radio noise for the four seasons, spring, summer fall, and winter, are given. The statistics were obtained from detailed computer analysis of high-dynamic range tape recordings of the noise process...

A total of six possible pairs of sites for a new U. S. Coast Guard, long­range, HF radio station is evaluated. These six pairs of sites are made up of different combinations of four different transmitter sites and six different receiver sites. The an...

The Fl layer is not explicitly included in current ITS high frequency radio propagation predictions. Numerical maps of Fl layer characteristics, similar to those for F2, E, and Es characteristics now in use, were rejected in favor of a more concise r...

The present 2182 kHz communication between Ketchikan, Alaska, and ships or boats within 300 nautical miles of Ketchikan Coast Guard Station is poor. Calculations have been made of predicted sky-wave mode performance for representative circuits with s...

The area in the Gulf of Mexico covered 85 percent of the time in the noisiest CCIR time block by the Coast Guard is calculated based on standard ground wave propagation and CCIR noise predictions. Most of the Gulf within 300 miles of the shore is cov...

Radio navigation systems such as Loran C,D operate on ground waves over distances up to 3000 or 4000 km from the transmitters. If the ground is inhomogeneous and irregular, the wave propagation may be considerably different from the classical smooth,...

High altitude nuclear detonations yield X-rays which produce intense ionization in about 1 jJ. s at heights much lower than those of the normal D region. The ionization begins to decay immediately. This leads to a very complicated profile of ionizati...

The feasibility of angle diversity reception over a 404 km obstacle­diffraction link in southern Europe was investigated during the summer of 1969. The primary objective of the measurement program was to determine the effectiveness of an experimental...

Comparisons are made between all the past measurements of Minuteman launch control type receivers, and these measurements are compared with the theoretical performance for receivers of this type acting in atmospheric noise. Comparisons are made for b...

This study presents one-way error correcting techniques for IGOSS (Integrated Global Ocean Station System) channels. Emphasis is on applicable HF radio experiments and alternative simple implementations. The "most promising" 1/2 rate code for IGOSS i...

1. The F2-region ionospheric response to individual internal gravity wave s is calculated as a function of the azimuth of wave propagation. The physical basis for the great anisotropy of the ionospheric response is discussed. 2. We present computer...

This report summarizes and presents in mathematical, graphical, and tabular form the fundamental characteristics of basic analog and digital modulation processes used in the Air Traffic Control (ATC) communication system. Single channel modes of ...

This report describes a study by the Institute for Telecommunication Sciences (ITS), to plan a moderate expansion of the National Crime Information Center communication system. Improvements discussed are transmission of data at higher rates than curr...

Use of a decibel plot for the Bessel function makes it a simple task to obtain the single tone peak deviation of FM radio systems. The procedure offers ways to calibrate deviation meters, supplement the carrier disappearance technique, and check the ...

Swept frequency (CHIRP) modulation is analyzed as to its suitability for use in the Integrated Global Ocean Station System (IGOSS), a system for the collection of synoptic data from ocean platforms (buoys and/ or ships) using high frequency (HF) radi...

This report proposes and compares convolutional codes with the (15,5) BCH code. Word-error probabilities are computed for each of the codes with the convolutional codes performing at least an order of magnitude better than the (15,5) BCH code. The co...

This paper describes instrumentation for recording digitally the relative phase and amplitude of MF and HF radio signals back­scattered from ocean waves. Eight stepped frequencies, two spaced receiving antennas, and four different ranges are used. T...

Rainguage data measured at the sub-common volume points when converted to an equivalent radar reflectivity and plotted in terms of a cumulative distribution correlates well with the similar cumulative distributions for the bistatic reflectivity for t...

This report reviews the techniques for calculating position with the Loran navigation system, including the use of phase correction factors computed for ground wave propagation over a smooth spherical earth. If the earth is rough or inhomogeneous, th...

A computer program. for calculating ground wave propagation in an ionized atmosphere is documented and listed. The conductivity of the atmosphere can vary in an arbitrary way with altitude. The notion of continuous stratification of the profile has b...

An operational one -way error correcting system is described that employs an interleaved block code with one -third rate and minimum distance decoding. For each decoded output character, the receiver also provides the minimum distance count. All timi...

It is shown that the optimum receiver for coded binary noncoherent Fre­quency Shift Keying (FSK) depends on the Joint probability distribution of mark and space channel phases. Ideal Gaussian noise, steady signal, and perfect timing are assumed throu...

The Institute for Telecommunication Sciences with the aid of the U. S. Bureau of the Census has undertaken a study of the distribution of the population within 10, 20, 30, 40, 50, 60, and 70 miles of 1120 selected television market centers within the...

Intensive radio and meteorological measurements were conducted on two beyond-the-horizon links during January, February, and March of 1970 to investigate the possible causes of severe fading and to determine corrective action for existing paths in th...

A description of the development and details of a range estimation computer program is presented. The program was tested with about 1700 range estimates with known sources. While the median range estimate errors generally fell in the 5-10 percent ran...

This report describes many of the UHF propagation characteristics between aircraft or satellites and buried antennas. A vertical monopole was used as a reference antenna, and the propagation characteristics of an annular slot and other antennas, omni...

A theoretical study has been performed of the radio frequency inter­ference (RFI) environment for existing electronic equipment and a proposed WSR-57 /MCW weather radar system installation on Holston Mountain and at Tri-City Airport, Tennessee. There...

Ground-to-ground path loss measurements are tabulated and discussed for paths terminated in surface and buried antennas, with and without security fences. Both horizontally and vertically polarized antennas at 415.9 MHz were used. Path lengths varied...

During the spring of 1969, measurements of received signal level, message channel quality, and other pertinent system parameters were made on two radio links of the Integrated Wideband Communication System in Thailand. The program was initiated to in...

In this period the HF timeshare program was updated to include circuit reliabilities under Task I. For Task II an investigation showed that variation of foFl could be satisfactorily represented by a formula expressing the dependence of foFl on solar ...

An ionospheric channel simulator with characteristics based on an experimentally verified channel model is described. In the channel model, the input (transmitted) signal feeds a delay line that delivers undistorted delayed versions of the input sign...

This report describes a feasibility study of an HF telemetry system to be used in gathering oceanographic and meteorological data from 35 buoys. Predictions of long-term circuit performance show that such a telemetry system of nominal characteristics...

A method of estimating the basic transmission loss, Lb, for VHF/UHF links that have low or buried antennas surrounded by security fences is presented, Estimates of Lb obtained are compared with experimental data.

Received signal level recording on two long line-of-sight paths with a common terminal showed that a relatively steep path elevation angle will not eliminate occasional deep fading. Most of the deeper fading occurred during periods of weak winds when...

Correlation measurements at a limited number of arbitrary locations were made during the feasibility study of frequency sharing between VHF TV and the Land Mobile Radio Services. Results of the data analysis are presented here in terms of cumulative ...

Simulcast is a system of broadcasting in which several carriers, each containing the same information and having equal frequencies, are used. In such a system, transmitter frequency drift, random phase between transmitters, and other factors will cau...

A multiple transmitter system, where transmitters at different locations send the same message simultaneously, was tested in the laboratory under simulated typical conditions. The results agreed very closely with those obtained theoretically and show...

Laboratory and field te sts we re performed to inve stigate the nature of interference fading from multiple sources. Fading fre quency, rates, and depths were measured, and conditions expected at actual sites common to several paths were investigated...

This paper poses, and attempts to answer, some of the questions involved when a UHF antenna is buried in the ground. A description of the basic theory is given, together with illustrative calculations for many situations of interest. Graphs are prese...

This report reviews antenna configurations for use on an ocean data buoy platform. Both electrical and mechanical requirements are con­sidered. A sleeve dipole antenna appears most suitable for small buoys. For large buoys. a discone antenna should b...

The effects of multipath arising when a signal transmitted from a User satellite is scattered by the earth before reaching a tracking and delay relay satellite (TRDS) in stationary orbit are considered. An upper bound for the probability of the scatt...

A numerical technique for mapping irregular terrain is described. The input data are fitted with a finite series of Gaussian functions, and a computer program evaluates the unknown constants in the functions. Two numerical examples are considered, ...

An estimate of the existing HF electromagnetic interference environ­ment was made for the U. S. Navy receiving antenna area in Bremerhaven, Germany. The estimate was based on land use in the area and measure­ments of man-made radio noise from various...

An algorithm is presented which permits calculation of the transmitter power required to achieve a given value of circuit reliability or service probability and time availability on high-frequency ionospheric tele­communication systems. The accuracy ...

Continuous wave signals at 9. 6 GHz were propagated over a 97 -KM overwater path extending from 80 m to 3000 IT) above mean sea level. Variations in phase of arrival of the signals received by antennas having 1. 2 and 5* beam widths were recorded sim...

The results of three research projects for the period January 1968 through December 1968 are reviewed. The first was to develop a program (ALLMODES) that presents circuit data for the 7 most probable ionospheric sky-wave transmission modes. The secon...

This memorandum describes FORTRAN routines for printer-plotting distribution functions on a normally scaled graph. Included are related routines for handling distribution functions.

Based on trends of recent ionospheric and solar data, the IPR series of Semimonthly Revision Factors for ITS Ionospheric Predictions provides corrections to the monthly ITS Ionospheric Predictions for F2-layer MUF. Accuracy of the IPR revision factor...

An evaluation of three refractivity variables in terms of their value in correcting microwave slant-range data for atmospheric effects is described. Experiments were conducted in Hawaii in 1967 on a fixed, 65 km overwater propagation path. The data o...

A hypothetical aircraft-to-ground communication channel is examined for frequencies in the 2 -30 MHz band, and in the 200 -400 band. The channel is characterized by its correlation function and scatter function. Particular attention is given to the e...

An investigation of radar microwave relay outages resulting from excessive fading on the line-of-sight microwave relay system indicated that most were caused by multipath propagation which resulted in phase interference fading. Rain attenuation was...

The ESSA/ITS HF system performance prediction program has been modified and adapted to operate on a time-share computer. The problems and solutions of implementation are discussed. A description is given of the routines used in the prediction program...

This report describes an experiment in which some computations are compared with available field strength data. Several models are proposed which compute an effective height by using a least squares fit to various sections of the terrain profile. Als...

This report is a system description and performance evaluation of a two-way system for communicating between a shore station and one or more ocean buoys or ships. The probabilities of various errors of omission and commission are considered. It is co...

This manual describes services provided by the Telecommunication Services Center to support operation of high-frequency ionospheric communications systems. The communicator obtains services he requires by a TTY terminal in his facility. Use of a dedi...

Atmospheric radio-noise samples were recorded near Boulder, Colorado, and analyzed to obtain amplitude and time statistics of MF and HF noise. Amplitude and time statistics derived from the Hall model were com­pared with the corresponding measured st...

A theoretical study of the radio frequency interference (RFI) environment has been performed for an existing communication complex that uses VHF, UHF, and microwave communication equipment and is located On top of Capitol Peak in the State of Washing...

Supported by data taken over a 65-km. slant path with fixed terminals, this report suggests exploitation of the dispersion between radio and optical signals for studying the atmospheric errors in radio range measurements over propagation paths with a...

Near-zone field strengths are calculated both on axis and on a grid behind the high power electronically steerable HF radar array to be erected near Platteville, Colorado. These calculations and measurements of the shielding effectiveness of the buil...

Three FORTRAN computer programs for generating spherical Bessel functions are described. A brief discussion of the method of calculation and the capabilities of the programs is followed by a detailed "users manual". The program listings are included ...

Propagation measurements were made at 6. 8 GHz during August 1967 over a 65-km. line-of-sight path in Ohio. During three periods of severe fading, both space and frequency diversity provided marked improvement over nondiversity operation. Comparisons...

A method of high precision arithmetic has been devised for the CDC-3800 computer based on nonstandard type. The precision extends up to 324 bits for normal arithmetic operations, and up to approximately 310 bits for exponentiation.

Two charges of TNT, each 100,000 Ib in size and hemispherical in shape, were detonated at ground level on the White Sands Missile Range, New Mexico. One function of the experiment was to measure the propagation and spectral characteristics of the aco...

The radiation patterns and power gains of two HF corner reflector array antennas --a two-element corner-reflector array antenna. rotatable in azimuth and operating from 10 to 27 MHz, and a 20-element corner­reflector array antenna mechanically fixed ...

This report presents the results of laboratory tests conducted to make preliminary determination of the required protection ratios for satisfactory sharing service in a VHF ATC communications system. The data given may be used to predict a quantitati...

This report is a supplement to ESSA Tech. Report IER 54-ITSA 52 by the same authors. Two additional models of log-periodic dipole arrays over several types of ground are studied in the present work. The total field above the ground is computed and pl...

In this report is described a highly flexible digital data acquisitions system that can be duplicated for $8,000. The system is for VLF research, but it could be easily adapted to a wide variety of problems. It is capable of sampling up to 16 channel...

Observations of 9.2, 11. 2, 12.2, 13.6, 15.2, and 17.2 kHz Omega signals radiated from Forestport, New York, and from Haiku, Hawaii, as received at Boulder, Colo., and at Anchorage, Alaska, are presented. Phase and amplitude data collected at these f...

Most radio systems are designed with bandwidths that are wider than necessary, resulting in wasteful use of the radio spectrum and failure to fully utilize the system capacity. This report reviews efforts to multiplex additional communications channe...

Feasibility of using backscatter to assess the accuracy of simultaneous direction-of-arrival measurements indicates poorer direction-of-arrival readings when backscatter shows travelling ionospheric disturbances. (Applies to simple mode paths.) The t...

Ionospheric irregularities represent departures from the ambient of up to 50% in electron density. Periods of high magnetic activity exhibit direction-of-arrival deviations which are more frequent and of greater magnitude than quiet periods. Mills T ...

This final report contains the results of an extensive study program, the development of a method for evaluating candidate communication systems, and the design of a test plan to supplement the information from the study program and provide realistic...

During October and November 1966, propagation measurements were made on two-line-of-sight paths between the islands of Maui and Hawaii, utilizing paths of a nominal I-ns width at a carrier frequency of approxi­mately 9 GHz. Prime objective was to det...

Numerical maps of h IF, F2 were prepared for all 12 months of 1954, a solar cycle minimum year, and of 1958, a solar cycle maximum year. To fill major gaps in the world coverage of observed data for these years, we used some supplementary data observ...

Antenna performance measurements were made on five HF antennas to determine their acceptance as prototype antennas for the Air Force HF communication circuits. The impedances. power gain, and radiation patterns of two of the log periodic antennas are...

1. Path loss median values can be substantially greater than one might expect from simple line-of-sight calculations especially where one leg of the path is very long. 2. Small passive reflectors have application at frequencies considerably below 4 ...

An investigation of the performance of a 405 km obstacle -diffraction radio link between Germany and Italy was made during June and July J 966 to evaluate contributions of both the antenna system and local meteorological conditions to propagation out...

The definition of radiation efficiency is stated and the principles and practice s in measuring it are reviewed. Particular attention is given to the rhombic antenna because of its practical importance at HF and because its efficiency can be determin...

Significant channel characteristics of HF communication circuits are reviewed, with particular emphasis on their importance in the evaluation and selection of useful operating frequencies. Various theoretical and experimental results from several sou...

This report describes a means of measuring and analyzing the transfer characteristic of an HF channel in terms of the effects of the medium on 229 closely spaced sinusoids. The method involves transmission, reception, measurement, and computer analys...

To evaluate the performance of the Minuteman Radio Launch Control System, a number of factors were investigated. This report gives the results of the field measurement programs conducted by ITSA. In addition to the radio noise evaluation, measurement...

Observations of coherent backscatter from the surface of the sea, at range s up to 200 km, using a slightly modified ionosonde are described. The range of frequencies used was between 2.6 and 8.5 MHz corresponding to sea wave lengths of 58 -17m and ...

Technical information relevant to the solution of frequency sharing problems in the VHF band that are associated with the use of VHF for the aircraft/ satellite link of a synchronous satellite air traffic control system is included in this report. Sp...

A study has been conducted to evaluate selected complements of Band 7 frequencies (3-30 MHz) by the application of radio propagation data to a hypothetical deployment of ocean buoys about base stations in various geographic areas. The relative utilit...

The National Crime Information Center consists of a real time data acquisition and storage system plus an extensive telecommunications network to permit law enforcement agencies throughout the United States to enter data and to interrogate the system...

Numerical results concerning the disturbances caused by a typical category of slightly subrefractive or superrefractive thick tropospheric layers in line-of-sight propagation as well as the importance of total reflection from such layers. These refle...

To assist NAV/SEEC in the evaluation of locations for a NAVCOM receiving site, the Electromagnetic Interference Environment Program Area personnel conducted a field measurement and analysis program. Interference levels from base supported, man-made n...

The theoretical on-axis gains of 134 terminated rhombic antennas are calculated for vertical radiation angles from 0 degrees to 45 degrees.

The characteristics of oblique sounding and backscatter sounding are discussed. The requirements imposed upon antennas for either form of sounding are considered. The available antenna types are reviewed from the standpoint of their suitability for...

A description of several investigations concerning high frequency backscatter is presented. These deal with travelling ionospheric irregu­larities, topside sounder-bottomside backscatter sounder comparisons, backscatter Doppler observations, ray trac...

The National Institute of Standards and Technology (NIST) microwave power standards in waveguide consist of automated microcalorimeters and associated transfer standards. Each transfer standard is a bolometric dc substitution power detector (a therm...

This note describes the design and error analysis of a WR10 thermal noise power standard. This standard is designed to operate at the boiling point of liquid nitrogen with a noise temperature output accurate to ± 1 K.

This technical note is a detailed discussion of the electromagnetic quantity, spectrum amplitude, which is used to characterize broadband signals and noise. The definition of spectrum amplitude is presented in detail. Several practical means of gen...

This report contains a description of the Fixed Radar Spectrum Utilization Model. This model is automated and can be used to obtain: (1) a measure of spectrum crowding in a specific geographic area and radar frequency band, (2) a list of preferab...

General expressions are derived for estimating the errors in the sum or difference far-field pattern of electrically large aperture antennas which measured by planar near-field scanning technique. Upper bounds are determined for the far-field errors...

This report presents comprehensive methods of calculation which have been found useful either for explaining or for predicting cumulative distributions of transmission loss for a wide range of radio frequencies over almost any type of terrain and in ...

This Technical note was originally given limited distribution as NBS Report No. 5092, dated July 25, 1957. Since that time part of this report have been published in the following references: (1) K. A. Norton, "Low and medium frequency radio prop...

Ongoing NTIA/ITS research shows that it can be possible for 5G base stations to safely co-exist with safety-of-life radar altimeters. This video is a follow up to SP-22-560, “5G In-Air Field-Strength CoLT Measurements for Radar Altimeter Research."...

This brief video provides an overview of ITS's approach to taking RF measurements to provide data relevant to the topic of radio interference that might possibly occur from some U.S. 5G transmitters to band-adjacent airborne radar altimeter (radalt) ...

The topic of the 2020 International Symposium on Advanced Radio Technologies™ (ISART 2020), which took place fully virtually August 10–13, 2020, was “5G and a Zero Trust Network.” The symposium aimed to identify challenges for spectrum to be availabl...

This document provides an analysis of responses to the 5G Challenge Notice of Inquiry (NOI) issued by the National Telecommunications and Information Administration (NTIA) on behalf of the Department of Defense (DoD). This analysis was created by NTI...

The 13th Annual International Symposium on Advanced Radio Technologies, held in Boulder, Colorado, July 24–26, 2012, presented the second conference focused on Developing Forward Thinking Rules and Processes to Fully Exploit Spectrum Resources. Follo...

These are the proceedings for the 2011 International Symposium on Advanced Radio Technologies hosted by the National Telecommunications and Information Administration’s Institute for Telecommunication Sciences in Boulder, Colorado. The conference foc...

Have you ever wondered how a spectrum analyzer works, how to properly adjust all of the analyzer's parameters, or why a stair-step pattern initially appears on a spectrum analyzer screen when you turn it on? Do you know how to precisely calculate the...

Proceedings of the International Symposium on Advanced Radio Technologies/ClimDiff 2008

Proceedings of the International Symposium on Advanced Radio Technologies, February 26–28, 2007

The purpose of ISART is to explore the future use of existing and emerging radio technologies. To this end, the conference brings together a diverse collection of people from academia, business, and government to discuss not only the technical aspect...

The United States’ radiocommunication interests are global. Communications are the backbone of our economic and national security and radiocommunications are a critical component of the United States’ overall communications interests. Radio signals...

This is the third issue of the Proceedings of the International Symposium on Advanced Radio Technologies (ISART), and the value of these proceedings is starting to become evident. The purpose of ISART is to explore the future use of existing and e...

The Department of Commerce Boulder Labs were dedicated on September 14, 1954, in the shadow of World War II, and at the dawn of a bright future. This volume presents a snapshot of our research accomplishments in the half century since then. During th...

This marks the second year that we have published an ISART Proceedings. I am particularly proud of this accomplishment since I believe that the Proceedings provides the radio community with a valuable resource. Not only is this a peer reviewed public...

The International Symposium on Advanced Radio Technologies (ISART) originated as a forum to explore the current state of the radio art and to identify directions in which the technology would likely evolve in the future. While the early ISART meeting...

On behalf of the Secretary of Commerce, the National Telecommunications and Information Administration (NTIA) has prepared this report in response to Title XVII, Section 1705 of the National Defense Authorization Act for FY2001. It represents part of...

The study described in this report was undertaken by the National Telecommunications and Information Administration (NTIA) in response to a Federal Communications Commission (FCC) Notice of Proposed Rule Making (NPRM) concerning the operation of a ne...

The President signed an executive memorandum dated October 13, 2000, that stated the need and urgency for the United States to select radio frequency spectrum to satisfy the future needs of the citizens and businesses for mobile voice, high-speed dat...

The study described in this report was undertaken by the National Telecommunications and Information Administration (NTIA) in response to a Federal Communications Commission (FCC) Notice of Proposed Rule Making (NPRM) concerning the operation of a ne...

On behalf of the Secretary of Commerce, the National Telecommunications and Information Administration (NTIA) has prepared this report to the President and the Congress as required by Title X of the National Defense Authorization Act for Fiscal Year ...

The 2000 International Symposium on Advanced Radio Technologies will focus on state-of-the-art and future trends in broadband wireless technologies and applications. Session presentations by leading experts in broadband communications from governmen...

The availability of the radio spectrum in the United States is critical to over 40 radio services that provide functions ranging from air traffic control to amateur radio operations. Although the radio frequency spectrum is not a consumable resou...

This is a joint report of the National Telecommunications and Information Administration (NTIA) and the Rural Utilities Service (RUS) in response to a request by ten U.S. Senators that NTIA and RUS examine six issues related to the availability and d...

The 1999 International Symposium on Advanced Radio Technologies will focus on state-of-the-art and future trends in satellite communication technologies and applications. ession presentations by leading experts in satellite communications from gover...

On behalf of the Secretary of Commerce, the National Telecommunications and Information Administration (NTIA) has prepared this report as required by Title III S Communication and Spectrum Allocation Provisions S of the Balanced Budget Act of 1997 (T...

The National Telecommunications and Information Administration (NTIA), under a mandate from Congress to develop long-range spectrum plans, initiated the Strategic Spectrum Planning Program. As part of this long-term planning effort, NTIA released a r...

Communication and information technologies can reduce the barriers of distance and space that disadvantage rural areas. This report defines a set of distinct voice, computer, and video telecommunication services; describes several rural information a...

Connecting every classroom, library, hospital, and clinic in the United States to the National Information Infrastructure (NII) is a priority. It is critical for these public institutions to become and remain active participants in the NII, since the...

This report identifies radio spectrum currently used by the Federal Government for reallocation to the private sector. It provides an overview of the reallocated bands, indicating the Federal usage, transition timetable, and any needed sharing requir...

This report documents the development of recommendations for a national approach to augmented Global Positioning System (GPS) services. The Institute for Telecommunication Sciences led a study team that included the U. S. Army Topographic Engineering...

This report reassesses U.S. communications and mass media policies in light of the increasingly global nature of the electronic mass media. A basic theme of this report is that the United States cannot afford to be complacent about the success of U.S...

This summary, in brief unclassified form, describes the varied requirements for the use of the radio frequency spectrum by the Departments and agencies of the Federal Government. This spectrum dependence has been dictated by the respective mandated f...

This report documents the learning experience of a group of Federal-agency planners who face upgrading or augmenting existing on-premises communication systems and building wiring. In July 1984, an interagency Fiber Optics Task Group was formed under...

This report examines the trade and related effects of possible changes in the 1982 AT&T consent decree.

The Federal Telecommunications Standards Cammi ttee, chaired by the Office of the Manager, National Communications System, has established a Fiber Optics Task Group, one purpose of which is to develop guidelines for Federal agencies planning to use f...

This report provides an analysis of marketplace developments and procompetitive U.S. policies for the past 15 years, and undertakes a net assessment of the benefits and costs of competition in 14 separate telecommunications and related lines of comme...

An analysis of issues in domestic telecommunications with recommendations for national policy. The report focuses on seven major areas: (1) development of technology; (2) structural and other constraints on the telecommunications industry; (3) prospe...

Microwave Radiation at the U.S. Embassy in Moscow and its Biological Implications: An Assessment

A nation’s international information policies do not exist in a vacuum, but rather are an extension of its domestic information policy perspectives. Thus, before any nation can adequately represent the interests of its own society in international fo...

The Office of Telecommunications "Telecommunications for Government" conference provides a forum for discussion of selected telecommunications applied research/engineering efforts by representatives of Government Agencies. Current research programs ...

This document is a technical dictionary containing approximately 300 terms, concisely defined for the communication engineer, covering the field of optical fiber waveguide communications. It was superseded by NBS Handbook 140 of the same title is...

This document is intended to provide guidance in planning Emergency Medical Systems [sic] (EMS) communications. Processes and and procedures are presented for such planning. Recommendations for obtaining technical, consultative and other assistance...

This publiction discusses technical and economic aspects related to the fixed-satellite and broadcasting-satelliate services. Planning studies in support of the 1979 General World Administrative Radio Conference (GWARC) are presented for the frequenc...

This 27-page report details use of the electromagnetic radio spectrum by U.S. Government military services and U.S. Government civil agencies. It also includes a list of Selected Government Frequency Assignment Data as of June 1, 1978.

Spread spectrum (SS) systems either are being planned or are already operational in the communications, radar, and navigation services. Since SS systems tend to increase the efficient use of the increasingly congested radio spectrum, spectrum manage...

This report is an initial attempt to identify and emphasize needs for radio spectrum and for related spectrum research to serve as the basis for planning for Efficient Use of the Spectrum Program at OT/ITS. However, any need or requirement for spectr...

The Office of Telecommunications "Telecommunications for Government" conference provides a forum for discussion of selected telecommunications applied research/engineering efforts by representatives of Government Agencies. Current research programs ...

This bibliography lists publications describing the scope, time span, depth, variety, and relevance of the satellite work done by the Institute for Telecommunication Sciences from 1958 through 1976. Works cited are listed by author with six categorie...

The Office of Telecommunications "Telecommunications for Government" conference provides a forum for discussion of selected telecommunications applied research/engineering efforts by representatives of Government Agencies. Current research programs ...

On March 2, 3, and 4, 1976, the Institute for Telecommunication Sciences of the Office of Telecommunications, U. S. Department of Commerce, sponsored a conference on "The Use of Millimeter Waves for Communications." The purpose of the meeting was to...

These user reaction tests involved voice telephone communications that were relayed one, two, or three times through the Westar satellite. The types of connections for the voice transmissions involved Common Control Switching Arrangements

The purpose of the paper is to explore the nature of the problem and to suggest some measures which might help to restore the U.S. effectiveness in the International Telecommunication Union (ITU), the oldest of the world's international organizations...

The Office of Telecommunications "Telecommunications for Government" conference provides a forum for discussion of selected telecommunications applied research/engineering efforts by representatives of Government Agencies. Current research programs ...

The Office of Telecommunications "Telecommunications for Government" conference provides a forum for discussion of selected telecommunications applied research/engineering efforts by representatives of Government Agencies. This third conference focu...

This report presents a compilation and discussion of Hawaiʻi's telecommunications resources and requirements, and of the domestic satellite system applications in FCC Docket No. 16495. This information should be useful in the analysis and planning of...

This is the third edition of a handbook intended to help Institute for Telecommunication Sciences (ITS) staff produce reports and papers in accordance with ITS, National Telecommunications and Information Administration, Department of Commerce, and F...

This is the third edition of a handbook intended to help Institute for Telecommunication Sciences (ITS) staff produce reports and papers in accordance with ITS, National Telecommunications and Information Administration, Department of Commerce, and F...

The Web-Enabled Subjective Test software allows researchers to conduct subjective tests on multiple devices with aggregated data collection and reporting. The system leverages modern web technologies and infrastructure to deliver test stimuli to typi...

This handbook provides a user’s manual for the batch video quality metric (BVQM) tool. BVQM runs under the Windows XP® or Windows 7® operating systems. BVQM performs objective automated quality assessments of processed video clip batches (i.e., as ou...

This handbook provides a user’s manual for the batch video quality metric (BVQM) tool. BVQM runs under the Windows XP® or Red Hat Linux® operating systems. BVQM performs objective automated quality assessments of processed video clip batches (i.e., a...

This handbook provides a user’s manual for the batch video quality metric (BVQM) tool. BVQM runs under the Windows XP® or Vista® operating systems. BVQM performs objective automated quality assessments of processed video clip batches (i.e., as output...

This handbook provides a user’s manual for the batch video quality metric (BVQM) tool. BVQM runs under the Windows XP® or Red Hat Linux® operating systems. BVQM performs objective automated quality assessments of processed video clip batches (i.e., a...

The purpose of this handbook is to provide a user’s manual for the in-service video quality metric (IVQM) tool. IVQM performs automated processing of live video signals. This program runs under the Windows XP® operating system on two PCs communicatin...

The purpose of this handbook is to provide a user's manual for the in-service video quality metric (IVQM) tool. IVQM performs automated processing of live video signals. This program runs under the Windows XP® operating system on two PCs communicatin...

This handbook provides a user’s manual for the batch video quality metric (BVQM) tool. BVQM runs under the Windows XP® operating system. BVQM performs objective automated quality assessments of processed video clip batches (i.e., as output by a video...

The purpose of this handbook is to provide a user’s manual for the in-service video quality metric (IVQM) tool. IVQM performs automated processing of live video signals. This program runs under the Windows XP® operating system on two PCs communicatin...

The purpose of this handbook is to provide a user’s manual for the video quality metric (VQM) tool. The VQM software tool performs automated batch processing of video files. Program VQM runs under the UNIX operating system and uses a control file to ...

This handbook is intended to provide estimates of radio wave propagation loss between transmitting and receiving antennas of various heights and transmission frequencies above the assumed smooth–earth surface calculated using the NLAMBDA computer mod...

This handbook contains instructions for operating the Refractivity Index Profile program. The RIP program is designed to calculate, tabulate, and plot the atmospheric refractivity index profiles for a given set of atmospheric data taken at a particul...

This handbook is intended to assist in manual analysis techniques that must be used when an automated analysis is not possible. It provides estimates of radio wave propagation loss between transmitting and receiving antennas above the assumed smooth-...

Speech quality and speech intelligibility can vary dramatically across the wide range of currently available telecommunications systems, devices, and operating environments. This creates a strong demand for efficient real-time measurements of quality...

This article provides a comprehensive overview of no reference (NR) metrics for image quality analysis (IQA) and video quality analysis (VQA). We examine 26 independent evaluations of NR metrics (previously published) and analyze 32 NR metrics on six...

This paper calculates confidence intervals for 89 datasets that use the 5-level Absolute Category Rating (ACR) method to evaluate the quality of speech, video, images, and video with audio. This data allows us to compute the subjective test confidence ...

Recent studies have shown that it is possible to characterize subject bias and variance in subjective assessment tests. Apparent differences among subjects can, for the most part, be explained by random factors. Building on that theory, we propose a ...

Channel sounders are used to measure channel characteristics for radio systems. There are several types of channel sounders used today: continuous-wave (CW), direct pulse, frequency domain using a vector network analyzer (VNA), correlation-based, and...

In situ measurements of radio frequency (RF) spectrum activity provide insight into the physics of radio frequency wave propagation and validate existing and new spectrum propagation models. Both of these parameters are essential to supporting and pr...

We need data sets of images and subjective scores to develop robust no reference (or blind) visual quality metrics for consumer applications. These applications have many uncontrolled variables because the camera creates the original media and the im...

The conventional video subjective test design, in which subjects view and rate multiple versions of each source video sequence, was used for decades. New technology, like adaptive streaming, makes it almost impossible to use this design since much lo...

A video is not always an accurate representation of what a first responder sees at an incident. New research suggests that first responders would benefit from a camera that removes airborne obscurants and shadows before the video is compressed. Curre...

How accurately are people able to use the absolute category rating (ACR) 5-level scale? Put another way, how repeatable are an individual subject’s scores? Several subjective experiments have asked subjects to rate the same sequences a couple of time...

This article describes the architecture of ITS-developed Propagation Modeling Website (PMW) tools that use commercial geographic information systems to both acquire geographic data and display geographic coverage areas. The PMW integrates commercial,...

This article describes how to perform a video quality subjective test. For companies, these tests can greatly facilitate video product development; for universities, removing perceived barriers to conducting such tests allows expanded research opport...

We announce a new Video Quality Model (VQM) that accounts for the perceptual impact of variable frame delays (VFD) in videos with demonstrated top performance on the Laboratory for Image & Video Engineering (LIVE) Mobile Video Quality Assessment (VQA...

During 1993–1994, the T1A1 subcommittee of the American National Standards Association (ANSI) accredited Alliance for Telecommunications Industry Solutions (ATIS) conducted an objective video quality metric validation test focused on video teleconfer...

This paper introduces ITU-T Recommendation P.913, a new subjective video quality testing standard approved in January 2014. This Recommendation focuses on the evaluation of flat screens, laptops, and mobile devices. P.913 emphasizes flexibility of en...

This paper presents recommended techniques for choosing video sequences for subjective experiments. Subjective video quality assessment is a well-understood field, yet scene selection is often driven by convenience or content availability. Three-dime...

The difficulty of finding and getting rights to use the high quality video sequences needed for video quality research has hampered research in this area for many years. This article describes the Consumer Digital Video Library (CDVL) website (www.cd...

Traditionally, audio quality and video quality are evaluated separately in subjective tests. Best practices within the quality assessment community were developed before many modern mobile audiovisual devices and services came into use, such as inter...

The perceived quality of an audiovisual sequence is heavily influenced by both the quality of the audio and the quality of the video. The question then arises as to the relative importance of each factor and whether a regression model predicting audi...

How much bandwidth is required for good quality video for a given screen resolution? Data acquired during two Video Quality Experts Group (VQEG) projects allow at least a partial answer to this question. This international subjective testing produced...

Subjective testing is the most direct means of assessing multimedia quality as experienced by users. When multiple dimensions must be evaluated, these tests can become slow and costly. We present gradient ascent subjective testing (GAST) as an effic...

The intent of H.264 (MPEG-4 Part 10) was to achieve equivalent quality to previous standards (e.g., MPEG-2) at no more than half the bit-rate. H.264 is commonly felt to have achieved this objective. This document presents results of an HDTV subjectiv...

For industry, the need to access accurate and reliable objective video metrics has become more pressing with the advent of new video applications and services such as mobile broadcasting, Internet video, and Internet Protocol television (IPTV). Indus...

The National Telecommunications and Information Administration (NTIA) General Model for estimating video quality and its associated calibration techniques were independently evaluated by the Video Quality Experts Group (VQEG) in their Phase II Full R...

Video quality metrics (VQMs) have often been evaluated and compared using simple measures of correlation to subjective mean opinion scores from panels of observers. However, this approach does not fully take into account the variability implicit in t...

In this study we investigated the geometric optics (GO) approximation to the fields of an infinitesimal electric dipole above a half plane for geometries typical of wireless indoor communications. This inspection was motivated by efforts to establish...

Perceived speech quality is most directly measured by subjective listening tests. These tests are often slow and expensive, and numerous attempts have been made to supplement them with objective estimators of perceived speech quality. These attempts ...

Part 1 of this paper describes a new approach to the objective estimation of perceived speech quality. This new approach uses a simple but effective perceptual transformation and a distance measure that consists of a hierarchy of measuring normalizin...

Multipath effects in indoor wireless communication systems exhibit a characteristic power delay profile (PDP) and can be a detriment to the system's performance. We present a simplified model for calculating the decay rate of the PDP for propagation ...

In 1996, the American National Standards Institute (ANSI) adopted ANSI T1.801.03, which presents a number of new objective video quality metrics for quantifying the effects of digital compression and transmission impairments. The measurements in ANSI...

Significant research and development efforts by industry and government laboratories were brought to fruition in 1996 with the approval of American National Standard (ANSI) T1.801.03 entitled "American National Standard for Telecommunications - Digit...

Discusses the standardization of user-oriented, technology-independent measures of telecommunication service quality, including voice, video, and data performance standards. Standards committee work has progressed in three broad phases. In the first ...

The Institute for Telecommunication Sciences (ITS) has recently completed a program to measure the impulse responses of channels that would probably be used in over-the-air HDTV. To help in the analysis of these measurements, we have developed a...

Over 5000 absolute absorption values for pressure-broadened O2 lines in dry air were measured at frequencies from 49 to 67 GHz in 0.1-GHz-increments. The controlled laboratory studies were carried out at three temperatures (6, 30, and 54°C) for 11 ...

Using empirical fits to published data, formulas are suggested for the complex permittivity of ice. The radio frequency may range from 0 to 1000 GHz, and the temperature from 0° to -40° C. It then becomes apparent where additional data would be welco...

Experimental permittivity data of liquid water, compiled from the open literature, were selectively applied to support a modeling strategy. Frequencies up to 1 THz and atmospheric temperatures are covered with an expression made up by two relaxation ...

A broadband model for complex refractivity is presented to predict propagation effects of loss and delay for the neutral atmosphere at frequencies up to 1000 GHz. Contributions from dry air, water vapor, suspended water droplets (haze, fog, cloud), a...

Interference coefficients describe the non-Lorentzian effect that arises as pressure broadening causes lines to overlap. These coefficients, one for each line, are at moderate pressures related linearly to absorption and dispersion. They are determin...

A general model of received signal variability is outlined in which the signal level is represented as a simple algebraic combination of random functions which, in turn, vary with time, location, and the "situation." A study of signal variability sho...

A practical atmospheric Millimeter-Wave Propagation Model (MPM) is formulated that predicts attenuation. delay, and noise properties of moist air for frequencies up to 1000 GHz. Input variables are height distributions (0–30 km) of pressure, temperat...

Absolute attenuation rates due to water vapor and moist nitrogen have been measured in the laboratory at 138 GHz, 282 and 300 K, pressures up to 1.5 atm, and relative humidities from 80 to 100 percent. The computer-controlled measuring system is ...

Spectrum occupancy for channels and bands of similar channels is defined. A distinction is made between transmission occupancy and message occupancy. The measurement time required to determine if a given channel is occupied is considered as well as t...

The line shape of the self-broadened rotational (5−1 → 6−5) transition of water vapor at v 0 = 22.235 GHz has been investigated on the basis of resonance dispersion information. Detailed information on absolute intensity, width, shift, and wing respo...

This paper describes U.S. spectrum management measurement challenges and a potential scalable solution using satellite-based observations. Specifically, we investigate the radio frequency passive imaging technique of synthetic aperture source localiz...

This paper proposes a mid-band statistical propagation model in which objective clutter metrics derived from lidar data provide the means to predict the distribution of clutter loss. Model performance is compared with 3.5 GHz propagation measurements...

This paper examines the estimation of the local mean voltage of a radio signal in a Rayleigh fast-fading environment. We focus on the statistical uncertainties of local voltage averages obtained by both integrating the voltage envelope of a specified...

This article is intended to motivate and describe a new tropospheric scatter modelling and measurement validation effort that is underway at the Institute for Telecommunication Sciences (ITS). Immediately after World War II, there was a flurry of res...

This paper describes a new National Telecommunications and Information Administration (NTIA) effort focused on the development of methods to determine appropriate interference protection criteria (IPC) as a means to resolve contention around spectrum...

In June 2018, ITS performed mobile clutter measurements in Salt Lake City, UT at 1.7 GHz. This measurement campaign was designed for path geometries with larger take-off angles by placing the transmitter in the hills of the nearby mountains. The resu...

We demonstrate that the optimal audio signal processing frame duration in oracle binary masking and oracle magnitude restoration is determined by joint minimization of two antagonistic artifacts: temporal blurring (which increases with frame duration...

Objective speech quality and intelligibility estimators do not correctly assess speech generated by deep neural networks (DNNs). We use 256 speech files and subjective scores that cover 14 DNN speech conditions and 18 nonDNN speech conditions to show...

We present a set of relatively small-scale proof-of-concept experiments where we construct no-reference (NR) speech quality estimators that give reliable values of system-under-test (SUT) input speech quality in spite of the fact that NR estimators c...

Building on prior work we have developed a no-reference (NR) waveform-based convolutional neural network (CNN) architecture that can accurately estimate speech quality or intelligibility of narrowband and wideband speech segments. These Wideband Audi...

This paper describes ongoing work within the video quality experts group (VQEG) to develop no-reference (NR) audiovisual video quality analysis (VQA) metrics. VQEG provides an open forum that encourages knowledge sharing and collaboration. The VQEG n...

Propagation models are used to inform scientists and engineers on how radio propagation through an environment will affect the radio signal received on the other end of the link. Many propagation models have been developed: some are curve-fitting mod...

Geopositioning uncertainty degrades the usefulness of the data collected while conducting propagation measurements in the field. Researchers currently have access to highly detailed terrain, propagation, and locational data sets, but these data are u...

We present path gain results at 3,500 MHz from a mobile channel measurement campaign that was carried out at the ITS Table Mountain Field Site. The purpose of this effort was to validate measurements obtained from a prototype sliding correlator chann...

Video surveillance systems, designed to provide security, act like a guard in a watchtower-a security solution that has been well understood for thousands of years. Systems are designed to meet security needs of the customer who installs the system. ...

Interference protection criteria (IPC) determine the interfering signal power a system can tolerate when sharing spectrum with other services. IPC are typically determined by measurements, but good measurements are often hindered by restrictions on e...

Separating an acoustic signal into desired and undesired components is an important and well-established problem. It is commonly addressed by decomposing spectral magnitudes after exponentiation and the choice of exponent has been studied from numero...

This paper discusses a mobile propagation measurement in Los Angeles, CA and compares these measurements to the output from the Irregular Terrain Model (ITM). Propagation measurements are currently being used at the Institute for Telecommunication Sc...

We describe an advanced mobile channel sounder system that has been under development by engineers at NTIA’s Institute for Telecommunication Sciences since 2010. We provide a description of the channel sounder and the key system components. We then h...

We present ABC-MRT16—a new algorithm for objective estimation of speech intelligibility following the Modified Rhyme Test (MRT) paradigm. ABC-MRT16 is simple, effective and robust. When compared to subjective MRT data from 367 diverse conditions that...

This paper discusses mobile propagation measurement campaigns in San Diego, CA; Denver, CO; and Washington, D.C. These measurements were made to inform possible clutter models in the 1755-1780 MHz band. This band was recently auctioned and will now b...

This paper presents a subjective image quality experiment design that specifically targets understanding consumer perception of visual quality. With this consumer-oriented goal in mind, images were captured from a large number of representative consu...

The new video coding standard, MPEG-H Part 2 High Efficiency Video Coding (HEVC) or H.265, was developed to be roughly twice as efficient as H.264/AVC—meaning H.265/HEVC could deliver the same quality as H.264/AVC using roughly half the bitrate. In t...

The separation of acoustic signals is often accomplished through subtractive decompositions of frequency-domain representations. This is typically enabled by the zero phase approximation or the uncorrelated signals approximation but both of these are...

Traditional 35mm film cameras are no longer the main devices today’s consumers use to capture images. Though the dominant technology has shifted to digital cameras and displays that differ widely in pixel count and resolution, our understanding of th...

The Video Quality Experts Group (VQEG) is an international and independent organisation of technical experts in perceptual video quality assessment from industry, academia, and government organisations. The main goals of VQEG are to advance the field...

This paper provides an overview of a Spectrum Monitoring Pilot Program within the U.S. Department of Commerce. It provides background, motivation, goals, accomplishments, and plans for future work. We describe the development of a federated Measured ...

Consumers demand video delivery to a wide variety of multimedia capable playback devices in dissimilar contexts. Monitoring the quality of the network provides a preliminary indication of the video quality end-users can expect. However, more advanced...

This paper examines color from multiple perspectives. A theory is proposed that the current color spaces are poorly designed for video quality and video coding purposes. The implication is that objective video quality metrics could be improved by the...

We propose a model for rating behavior based on subject bias and subject error. Evidence for subject bias can be found in freely available subjective experiments. When subject bias is removed from ratings, the sensitivity of statistical comparisons b...

The measurement of a radar chirp waveform is critical to assessing its spectral compliance. The Fourier transform for a linear frequency-modulated chirp is a sequence of frequency-domain impulse functions. Because a spectrum analyzer measures the wav...

In response to the Presidential Memorandum on Wireless Innovation and the recommendation of the Presidential Council of Advisors on Science and Technology (PCAST), the federal government has begun the process of organizing a National Advanced Spectru...

An immersive subjective test method is proposed in which subjects view each source stimulus only once. In order to encourage a subject’s engagement with test content, longer stimuli are used. Distractor questions are used in addition to the tradition...

We present an objective estimator of speech intelligibility that follows the paradigm of the Modified Rhyme Test (MRT). For each input, the estimator uses temporal correlations within articulation index bands to select one of six possible words from ...

This paper describes objective video quality validation efforts conducted in the past two decades. Validation efforts to be examined include a validation test performed by the T1A1 committee in the early 1990's; five rounds of validation testing perf...

We provide detailed descriptions of recent radiated emissions measurements conducted by the National Telecommunications and Information Administration (NTIA) Institute for Telecommunication Sciences (NTIA/ITS) in Boulder, Colorado. ITS engineers perf...

This paper presents spectrum occupancy results from spectrum surveys conducted at three locations: Denver, CO; Table Mountain near Boulder, CO; and Point Loma, near San Diego, CA. Equipment setups are described along with the measurement algorithms u...

When communication systems operating in one band must be moved to another band occupied by existing (incumbent) systems, an electromagnetic compatibility (EMC) analysis is used to evaluate the viability of spectrum sharing and frequency reassignments...

In 2011, the Video Quality Experts Group (VQEG) ran subjects through the same audiovisual subjective test at six different international laboratories. That small dataset is now publically available for research and development purposes.

The lossless compression algorithm specified in ITU-T Recommendation G.711.0 provides bit-exact G.711 speech coding at reduced bit-rates. We introduce two Look-Up Coders (LUCs) that also offer bit-exact G.711 speech coding at reduced rates but the LU...

The value or harm associated with an increase in speech coding quality depends on the type of the increase as well as the temporal location of the increase in an utterance. For example, some increases in speech coding bandwidth can be perceived as im...

This paper explores the utility of visual acuity as a video quality metric for public safety applications. An experiment has been conducted to track the relationship between visual acuity and the ability to perform a forced-choice object recognition ...

This paper presents recommended techniques for choosing video sequences for subjective experiments. Subjective video quality assessment is a well understood field, yet scene selection is often limited by content availability. The Consumer Digital Vid...

Complete and accurate characterization of the radio environment is necessary for effective management of an increasingly congested radio spectrum. Unfortunately most antenna systems commonly used to perform spectrum surveys only respond strongly to s...

We describe a prototype propagation measurement system based on a combination of a spectrum analyzer and a vector signal analyzer. The system is designed to measure the characteristics of a narrowband mobile radio channel. We present results from a c...

Characterizing the effects that out-of-band interference has on the performance of an S-band marine radar receiver’s IF output normally requires non-linear network analysis. We have developed a non-linear network analyzer from commonly available labo...

With increased demand in the radio spectrum, there have been multiple recent campaigns to quantify spectrum occupancy through measurements. These measurements can pose many challenges, one of which is created by impulsive noise. Below 500 MHz, impuls...

We explore the quality impact when audiovisual content is delivered to different mobile devices. Subjects were shown the same sequences on five different mobile devices and a broadcast quality television. Factors influencing quality ratings include v...

We present and evaluate a new multiple–description coding extension to the international standard for pulse code modulation speech coding (ITU–T Rec. G.711). This extension is inserted between the G.711 encoder and decoder. It uses speech–polarity de...

In advanced heterogeneous telecommunication networks, network resources can dynamically dictate the type of speech coding that is used. An increase in resources allows for lower coding distortion or it might also be used to provide wideband speech in...

We present the design, preparation, and analysis of a subjective experiment on typical HDTV sequences and scenarios. This experiment follows the guidelines of ITU and VQEG in order to obtain reproducible results. The careful selection of content and ...

The shortage of high quality video sequences has hampered video quality research for 20 years. Every Video Quality Experts Group (VQEG) test has encountered difficulty in obtaining quality source content. For some validation tests, this caused a mult...

This paper describes a mobile-to-mobile propagation measurement system that is currently being developed at the Institute for Telecommunication Sciences under the sponsorship of the Office of Spectrum Measurement. This system uses a fixed transmitter...

(This paper won the QoMEX 2009 Best Paper Award.) Subjective testing is the most direct means of assessing audio, video, and multimedia quality as experienced by users and maximizing the information gathered while minimizing the number of trials ...

Digital video transmission systems consisting of a video encoder, a digital transmission method (e.g., Internet Protocol – IP), and a video decoder can produce pauses in the video presentation that result from dropped or repeated video frames. For ex...

This paper describes a methodology for analyzing binary phase-shift keyed demodulator performance in the presence of various types of undesired signals. It utilizes models of the underlying random processes to determine the probability of a bit error...

While useful speech communication systems must be intelligible, most systems aim to transmit secondary information, such as attributes of a speaker's voice, as well. This secondary information can allow a listener to identify the speaker and his emot...

We describe an experiment where listeners were asked to detect two specific forms of stress in talkers' recorded voices heard via six different simulated communication systems. Both task–induced stress and dramatized urgency were used. Communication ...

Layered audio coding typically offers reduced distortion as bit rate is increased, but that distortion is spread across the entire band until the lossless coding bit rate is reached and distortion is eliminated. We propose a layered audio coding para...

The Public Safety Statement of Requirements (PS-SoR) for Communications and Interoperability focuses on the needs of first responders to communicate and share information as authorized, when it is needed, where it is needed, and in a mode or form tha...

This paper summarizes results from an experiment whose goal was to assess whether the NTIA General Video Quality Metric (VQM) is an acceptable objective metric for measuring High Definition TV (HDTV) video quality. The HDTV subjective test that was p...

We investigate the use of an adaptive processor (a quantizer pseudoinverse) and the statistics of the associated pseudoerror signal to reduce quantization error in scalar quantizers when a small amount of prior knowledge about the signal x is availab...

We have designed, conducted, and analyzed a subjective speech quality experiment with unrestricted timing where subjects can vote whenever their opinions are fully formed, rather than at fixed time intervals. Analysis of the resulting listening times...

We present a general formulation of a basic open question regarding the perception of time-varying speech quality. We then describe the design, implementation, conduct, and analysis of a practical experiment that addresses a small but fundamental par...

We describe new 2-channel multiple-description speech coders based on the ITU-T Recommendation G.711 PCM speech coder. The new coders operate in the PCM code domain in order to exploit the companding gain of PCM. They apply pairs of complementary asy...

We describe a 2-channel multiple-description speech coder based on the ITU-T Recommendation G.711 PCM speech coder. The new coder operates in the PCM code domain in order to exploit the companding gain of PCM. It applies a pair of 2-dimensional struc...

This paper presents a new reduced reference (RR) video quality monitoring system that utilizes less than 10 kbits/s of reference information from the source video stream. This new video quality monitoring system utilizes feature extraction techniques...

When objectively estimating speech, audio, or video quality, it is often necessary to compensate for a system gain or to "gain match" two or more signals. One can take three views of a system, leading to three different definitions of gain, and three...

In packetized speech transmission, end–to–end delay can vary, even over short timescales. Estimating the resulting speech delay histories is critical to diagnostic and quality estimation efforts. We present a new bottom–up algorithm for estimating ti...

International recommendations for subjective video quality assessment (e.g., ITU-R BT.500-11) include specifications for how to perform many different types of subjective tests. Some of these test methods are double stimulus where viewers rate the qu...

International recommendations for subjective video quality assessment (e.g., ITU-R BT.500-11) include specifications for how to perform many different types of subjective tests. In addition to displaying the video sequences in different ways, subject...

Temporal discontinuities in received speech are a reality of Internet Telephony or Voice over Internet Protocol (VoIP) systems. These relatively new impairments pose unique challenges to objective estimators of perceived speech quality. We suggest th...

Multiple–description coding is one way to gain robustness against lossy channels. We extend the multiple–description scalar quantizer (MDSQ) to a channel–optimized MDSQ (COMDSQ) that minimizes mean–squared error for a given channel environment. We di...

Over the past few years, there have been a number of proposals aimed at introducing different levels of service in the Internet. One of the more recent proposals is the Differentiated Services (Diff-Serv) architecture, and in this paper we explore ho...

This paper presents objective-to-subjective correlation results for a reduced-reference, in-service, video quality monitoring system. This reduced-reference system utilizes quality parameters that are computed by comparing features extracted from spa...

This paper identifies optimum levels of reverse water-filling for codebook-based coding of noise and speech signals. We find that there is little to be gained from optimizing an effective rate parameter. We identify trade-offs between SNR and log-spe...

The Institute for Telecommunication Sciences, part of the National Telecommunications has a long-standing program to develop radio channel measurement systems. This paper briefly reviews selected examples of recent measurements, outdoor and indo...

One of the questions that ongoing QoS efforts seek to answer is: "Given fixed network resources, how does one provide the highest possible quality of service to the maximal number of users in a fair way, even when those users are generating competing...

Many organizations have focused on developing digital video quality metrics which produce results that accurately emulate subjective responses. However, to be widely applicable a metric must also work over a wide range of quality, and be useful for i...

We present two techniques that can be used to enhance objective estimators of perceived speech quality. Frame normalization and frame-energy plane partitioning are described and applied to a log-spectral-error-based estimator. The resulting estimator...

With the advent of new digital video systems that utilize compression to achieve a savings in transmission or storage bandwidth, the quality of the received output video can be dependent not only upon the inherent spatial and temporal information con...

We present results of subjective viewer assessment of video quality of MPEG-2 compressed video containing wide-band Gaussian noise. The video test sequences consisted of seven test clips (both classical and new materials) to which noise with a peak-s...

Statistical noise models that simulate man-made noise are essential for the design of radio systems. Recently, the Institute for Telecommunication Sciences measured man-made VHF radio noise in the 136 to 138 MHz meteorological satellite band. The...

Frequency-domain companding can be used in conjunction with audio coders that produce white coding noise. In [1-2] it is demonstrated empirically that this technique colors white coding noise so that it is better masked by audio signals, resulting in...

This paper discusses the analysis of an audiovisual desktop video-teleconferencing subjective experiment conducted at the Institute for Telecommunication Sciences. Objective models of the individual audio and video quality are presented. Also discuss...

ITU-T Recommendation P.861 describes an objective speech quality assessment algorithm for speech codecs. This algorithm transforms codec input and output speech signals into a perceptual domain, compares them, and generates a noise disturbance value,...

We describe six algorithms for bit allocation in audio coding. Each algorithm stems from the minimization of a different perceptually–motivated objective function. Three of these objective functions are extensions of existing ones, and three are new....

We describe a new approach to the estimation of perceived speech quality. The approach uses a simple, but effective, perceptual transformation to emulate hearing and a hierarchy of Measuring Normalizing Blocks (MNB's) to emulate auditory judgment. Th...

We describe a listening experiment that measures the perceived speech quality of 19 speech passbands using 8 talkers and 28 listeners. Results are referenced to the traditional wide-band and narrow-band telephony passbands. Our findings may help thos...

Recently, The Institute for Telecommunication Sciences measured man-made noise in portions of the VHF and UHF bands. This paper provides an overview of the measurement and analysis methods used and examples of the results. The VHF measurements were m...

Excitation patterns and masking patterns are used extensively in perceptual audio coders and quality assessment algorithms. Numerous algorithms for calculating these patterns have been proposed. This paper provides comparisons among the patterns gene...

Four proposed perception-based techniques for objectively estimating speech quality and three traditional estimators are applied to coded speech samples. Agreement between objective estimates and corresponding subjective test scores is reported. Seve...

Objective (or instrumental) tests of speech quality have been proposed as ways to reduce the need for expensive and time-consuming subjective (or auditory) tests. Both types of tests attempt to quantify the range of opinions that listeners express in...

Propagation characteristics of the atmosphere are modeled for the frequency range from 1 to 1000 GHz (1 THz) by the modular millimeter-wave propagation model MPM. Refractivity spectra of the main natural absorbers (i.e., oxygen, water-vapor, suspende...

Measurements that quantify perceptual video attributes in both the spatial and temporal domains are extracted from the video that has undergone digital coding and compression. These measurements are then used to compute a single score that quantifies...

The Institute for Telecommunication Sciences (ITS) has developed an objective video quality assessment system that emulates human perception. The system returns results that agree closely with quality judgements made by a large panel of viewers. Such...

Gaseous atmospheric attenuation and delay properties in the 50 to 75-GHz band and near 119 GHz are dominated by the fine structure lines of molecular oxygen. With increasing altitude the complex refractivity displays spectral patterns which change...

Millimeter-wave propagation through the nonprecipitating atmosphere is modeled for frequencies below 1000 GHz. Complex refractivities represent the spectral properties of four natural absorbers; that is, oxygen, water-vapor, suspended droplets and ic...

Discusses the approach used and the research conducted to develop an objective video quality assessment system that emulates human perception. The system returns results that agree closely with quality judgments made by a large panel of viewers for t...

The O2-spectrum of dry air was studied with a resonance spectrometer under controlled laboratory conditions. Key parts of the instrumentation were an automatic network analyzer and a one-port Fabry-Pérot resonator affording an effective path length...

Discusses research efforts to derive objective measures of video quality that emulate human perception. The derivation of these metrics involves the following steps: (1) a set of test scenes in selected and distorted, (2) a set of candidate objective...

Two millimeter-wave propagation models, called MPM and MZM, are discussed. The first one predicts, at frequencies up to 1000 GHz, loss and delay effects for a nonprecipitating atmosphere. Contributions from dry air and vapor are addressed, as well as...

An investigation of the FM Broadcast Spectrum's utilization shows that more assignments are possible if some or all of the following recommendations are adopted: protections to existing facilities rather than to maximum facilities is granted the ...

The United States Department of Commerce (DOC) has been active in radio wave propagation research and prediction for several decades, and has provided the Federal Aviation Administration (FAA) with many propagation predictions relevant to the coverag...

It is desirable to design receiving sys­tems so that the receiver will be close to being limited by external noise. Indeed, it is cost ineffective to design radio receiving systems with noise figures significantly less than the minimum values of the ...

Peak Signal to Noise Ratio (PSNR) has been used as a benchmark to evaluate new objective perceptual video quality metrics. For example, PSNR has been used as a benchmark for both the Multimedia (MM) and Reduced Reference Television (RRTV) test progra...

Study Group 9 has been working on finalizing Draft New Recommendation J.redref which specifies Reduced Reference (RR) methods for performing video quality measurements of digital television systems. The U.S. National Telecommunications and Informatio...

This contribution presents new techniques for estimating temporal delays between input and output video streams from video teleconferencing systems. The discussion in this contribution considers "variable alignment," defined as an alignment process t...

This contribution presents a new technique for estimating temporal delays between input and output video streams from video teleconferencing systems. The discussion in this contribution is limited to "constant alignment," defined as an alignment proc...

This contribution aggregates the available performance data on the MNB and P.861 objective speech quality measures. Specifically, results presented in contributions T1A1.7/97-032 and T1A1.7/97-034 are examined. Based on examination of the aggregated ...

Presents an in-depth analysis and discussion of the results from applying the ANSI T1.801.03-1996 objective video quality metrics to subjectively rated MPEG-1 and MPEG-2 video test scenes. The objective metrics presented in ANSI T1.801.03-1996 (Ameri...

This contribution is provided for informational purposes. It contains a description of an algorithm that has sucessfully been used to estimate the delay of telephony band speech. The algorithm features a coarse stage that uses speech envelopes and a ...

Presents a computerized search method for determining the gain, level offset, active video shift, and video delay of a digital video transmission channel. The method uses digitized input and output NTSC video fields that have been time tagged with SM...

Recommends a process to be used by ANSI for duplication and traceability of video tapes for ANSI T1.801.02-1996 (American National Standard for Telecommunications - Digital Transport of Video Teleconferencing/Video Telephony Signals - Performance Ter...

Recommends a process to be used by ANSI for duplication and traceability of video tapes for ANSI T1.801.01-1996 (American National Standard for Telecommunications - Digital Transport of Video Teleconferencing/Video Telephony Signals - Video Test Scen...

This contribution recommends that calculations of visual channel delay be based on fields rather than frames for an interlaced video system such as NTSC. Using fields rather than frames will double the resolution of the measurement without significan...

Presents a summary of efforts to make the objective video quality metrics more efficient in terms of computation and transmission bandwidth. Objective to subjective correlation results are presented for the subjectively rated data set given in the 19...

Presents an objective analysis technique that can be used for detecting temporal edge noise in an output video sequence that has been digitally compressed. Temporal edge noise is defined in ANSI T1.801.02-1996 as "A form of edge busyness characterize...

Describes an algorithm for (1) quantifying the spatial gradients or edges in an image as a function of angle or orientation, (2) extracting low bandwidth features from these input and corresponding output spatial gradient images, and (3) deriving obj...

Provides an in-depth analysis of the behavior of the P6 video performance parameter, a parameter that measures the motion energy that is lost when a video scene is transmitted through a digital video compression system. Objective to subjective correl...

This contribution discusses the advantages and disadvantages of two methods for obtaining a composite rating of Hypothetical Reference Circuit (HRC) performance for an ensemble of source material. The term HRC refers to a specific realization of a vi...

Describes two objective measurements that can be used to quantify the spatial and temporal information content of a video test scene. Test scene coding difficulty (and hence video quality) often depend on the spatial and temporal information complexi...

Presents detailed intra-laboratory (within laboratory) and inter-laboratory (between laboratories) analysis of variance (ANOVA) results for the T1A1 subjective video experiment that contained 625 mean opinion scores (25 test scenes passed through 25 ...

Presents results from the analysis of variance (ANOVA) of the subjective opinion scores for the T1A1 subjective video experiment that contained 625 mean opinion scores (25 test scenes passed through 25 different video transmission systems that ranged...

This contribution presents objective to subjective correlation results for the traditional analog measurements of bandwidth (i.e., frequency response) and signal-to-noise ratio (SNR) for the T1A1 subjective video experiment that contained 625 mean op...

Presents in detail the ANOVA methods for analysis of the subjective T1A1 video test data, especially with regard to any systematic effect a laboratory may have on the Mean Opinion Score (MOS) of any given Hypothetical Reference Circuit (HRC). The ter...

Contribution T1A1.5/93-152 summarized the methods of measurement for objective video quality parameters based on the Sobel-filtered image and the motion difference image that were submitted prior to conducting the T1A1 subjective experiment (this exp...

Discusses the method of measurement used to obtain the signal to noise ratio (SNR) values for each of the twenty-five video systems in the T1A1 subjective video experiment. The 25 video systems ranged in bit rate from 64 kb/sec to 45 Mb/sec. The sign...

Discusses the method of measurement used to obtain the frequency response or bandwidth values for each of the twenty-five video systems in the T1A1 subjective video experiment. The 25 video systems ranged in bit rate from 64 kb/sec to 45 Mb/sec. The ...

Summarizes detailed methods of measurement for two objective video quality parameters based on the Fourier transform image. This contribution was submitted to ANSI T1A1 prior to conducting the T1A1 subjective experiment (this experiment collected 625...

Summarizes detailed methods of measurement for objective video quality parameters based on the Sobel-filtered image and the motion difference image. This contribution was submitted to ANSI T1A1 prior to conducting the T1A1 subjective experiment (this...

Working Group T1A1.5 is supporting ITU-T Study Group 12 in developing subjective audiovisual testing methods under Question 22/12 which addresses audiovisual quality in multimedia services. A previous contribution from Bellcore, T1A1.5/93-104, descri...

Discusses a real-time personal computer-based system for characterizing spatial (e.g., blurring) and temporal (e.g., jerky motion) distortions in a compressed digital video system. Comparisons with a high quality non real-time laboratory version of t...

Out-of-service measurements can be used to obtain a baseline video system delay. However, in many digital video systems, video delay is dynamic and dependent upon the scene content. This contribution describes an objective measure of video delay that...

The motion difference images of the original and degraded video sequences is used to dynamically measure the Transmitted Frame Rate (TFR) and the Average Frame Rate (AFR) of a digital video system codec (coder-decoder). The TFR measurement algorithm ...

Presents objective to subjective correlation results when the scores from multiple video test scenes are averaged. It is shown that the prediction errors of the objective video quality model are reduced, yielding objective measurement results that mo...

ATIS Committee T1 contribution to standards project “Analog Interface Performance Specifications for Digital Video Teleconferencing/Video Telephony Service and DS3 Television”

In a Study Group XII (Experts Group on Speech Quality) Contribution dated September 1991, John Rosenberger and Bill Cotton of Bellcore introduced an algorithm for generating temporally correlated distortion on 8 KHz sampled speech data. This distorti...

Presents an overview of metrics that can be used to quantify the amount of spatial and temporal information in a video sequence. By applying the metrics to the input and output video, the amount of spatial and temporal information that is lost by the...

Presents preliminary results on the objective to subjective quality correlation for a set of 5 test scenes passed through three systems (NTSC, VHS, and DS1 MPEG coding). One objective metric that correlates well with subjective quality quantifies the...

The ability of the human eye to resolve detail in a video scene is related to how much motion is present at the point of focus and whether or not the eye can track the motion. Thus, stationary portions of the video scene can be resolved in great deta...

Recommendation P.528 contains a method for predicting basic transmission loss in the frequency range 100-30 000 MHz for aeronautical services. This software published by the Institute for Telecommunication Sciences implements Annex 2 of Rec P.528, th...

In an extended P25/VoLTE public safety communication system voice signals will pass through both Multi-Band Excitation (MBE) and Adaptive Multi-Rate (AMR) speech coders. Thus it is important to quantify the speech quality that can be expected for MBE...

This guide focuses on a key portion (subsystem) of the radio communications system--the antenna system. Although the antenna itself may be the most visible element of radio communications equipment, it is often the least understood. This guide define...

Dedicated short-range communication systems have been proposed for operation at locations across the United States in the 5850- to 5925-MHz band. Various search and tracking high-power radars operate at or near this frequency band and are a source...

This report provides a description of the computational details in the IF-77 (ITS-FAA-1977) radio wave propagation model. The IF-77 model is useful in estimating service coverage for radio systems operating in the 0.1 to 20 GHz frequency range. It is...

S-Band Radar Pulse Densities in the Los Angeles Area

This report provides an atlas of air/ground and air/air basic transmission loss predictions made with the IF-77 (ITS-FAA-1977) propagation model. Sets of predictions are provided for each of six frequencies; i.e., 0.125, 0.3, 1.2, 5.1, 9.4, and 15.5 ...

This report provides extensive comparisons of measured propagation data with predictions made by the IF-77 (ITS-FAA-77) and other propagation models. Although IF-77 was developed for aeronautical applications, it can be used for some point-to-point p...

This report covers ten computer programs useful in estimating the service coverage of radio systems operating in the frequency band from 0.1 to 20 GHz. These programs may be used to obtain a wide variety of computer-generated microfilm plots such as ...

A U.S. Postal Service (USPS) electronic message system could incorporate many types of error control coding, or no coding at all. This report reviews a variety of possible codes, lists their advantages and disadvantages, and selects a preferred alte...

This is the sixth quarterly progress report on a study to obtain quantitative information on the additional attenuation suffered by radio waves traversing the auroral zone. For many years it has been known that ionospheric radio wave propagation...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA), an agency of the Department of Commerce (DoC). ITS serves as a principal federal r...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA), an agency of the Department of Commerce (DoC). ITS serves as a principal federal r...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA), an agency of the Department of Commerce (DoC). ITS serves as a principal federal r...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

This progress report describes the activities related to the Spectrum Sharing Innovation Test-Bed Pilot Program undertaken during Fiscal Year 2010.

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

This progress report describes the activities related to the Spectrum Sharing Innovation Test-Bed Pilot Program undertaken during Fiscal Year 2008.

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA ...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

The Institute for Telecommunication Sciences (ITS) is the research and engineering laboratory of the National Telecommunications and Information Administration (NTIA) of the U.S. Department of Commerce (DOC). ITS provides technical support to NTIA in...

This report documents a digital computer program for computing the propagation of LF and VLF radio waves using the wave hop theory. It supersedes NBS Report 8889. The documentation includes a description of the physical model, detailed mathematical f...

The propagation factor for wave propagation over an impedance surface containing irregularities large compared to a wavelength is the solution of a certain integral equation. The equation is solved numerically for the special case of a two-dimension...

This report provides information about research projects conducted at the National Bureau of Standards Department of Commerce Boulder Laboratories in FY 1961 by the Cryogenic Engineering Laboratory (CEL) and the Central Radio Propagation Laboratory (...

In this white paper, we describe a new convolutional framework for waveform evaluation, WEnets, and build a Narrowband Audio Waveform Evaluation Network, or NAWEnet, using this framework. NAWEnet is single-ended (or no-reference) and was trained thre...

The VQEG eletter publishes up-to-date technical advances on video quality related topics. The VQEG eLetter also makes available limited distribution publications that contain valuable technical information, such as out-of-print ATIS contributions. Th...

Researchers at the Institute for Telecommunication Sciences (ITS) in Boulder, Colorado are trying to make sure important emergency video comes through clearly. They are in the process of developing requirements for publicsafety video applicatio...

This white paper documents the algorithm of the ITM (the Irregular Terrain Model) as implemented in 1999. There are probably, however, some features of the model that are not documented here but present in the original Fortran source code. The purpos...

This study includes a description of the services provided in about 30 of the Government and non-Government frequency bands where Fixed services are accorded Primary status. These frequency bands between 406 MHz and 30 GHz include the services genera...

Measurements of Federal land mobile usage, in selected mobile bands, relating to the 1989 Presidential inauguration were made using NTIA's RSMS Van to assess Government communications requirements for a special event of national importance. This repo...

This report contains emission spectra and pulse characteristics of the ASR-8 radar. The measurement data was collected as part of the federal frequency management program of the National Telecommunications and Information Administration (NTIA), and i...

The basic reason for these measurements is to obtain a calibration constant for the Federal Aviation Administration's (FAA) flight inspection aircraft (a Convair 580). . . . In order to do this seemingly simple calibration, a known field strength is ...

These data provide the results of measurements made in April 1978 to determine the usage of Federal radio channels in the 406–420 MHz band at Norfolk, Virginia. These measurements were conducted as part of the National Telecommunications and Informat...

These data provide the results of measurements made in April 1978 to determine the usage of Federal radio channels in the 30–50 MHz band at Norfolk, Virginia. These measurements were conducted as part of the National Telecommunications and Informatio...

These data provide the results of measurements made in March 1978 to determine the usage of Federal radio channels in the 225–400 MHz band at Norfolk, Virginia. These measurements were conducted as part of the National Telecommunications and Informat...

These data provide the results of measurements made in March 1978 to determine the usage of Federal radio channels in the 162–174 MHz band at Norfolk, Virginia. These measurements were conducted as part of the National Telecommunications and Informat...

These data provide the results of measurements made in March 1978 to determine the usage of Federal radio channels in the 138–150 MHz band at Norfolk, Virginia. These measurements were conducted as part of the National Telecommunications and Informat...

Some basic concepts. design criteria and hardware implementations are reviewed for measuring the impulse responses which characterize radio transmission channels. A channel sounder which is presently being used by the Institute for Telecommunication ...

This report describes and illustrates the method, instrumentation and applications of a probing technique for measuring fundamental characteristics of a radio model transmission channel. The method is based upon a convolutional model of the channel, ...

The bibliography is a reference guide that cites and annotates over 400 articles on various aspects of telecommunications. Articles are relevant to U.S. policy in communications, and range from specific technologies and systems worldwide, to economi...

This catalog lists about 495 information products representing the results of the various OT programs. Section I contains an alphabetical listing, by title with abstract and key words, of technical reports, technical memoranda, special publicatio...

The papers in this publication were prepared for presentation at technical sales seminars in Yugoslavia, Romania and Poland from Sept. 20 to Oct. 10, 1974. Topics covered include: telecommunications research and development; telephone networks; switc...

The continued expansion of microwave radio links and the resulting congestion have increased the need for better performance estimates. In the evaluation of refractivity effects, the designer may wish to consider the average gradients at specific lo...

This report is designed to make the significance and usefulness of the CCIR more understandable to the engineer involved in systems planning and in operations. It is prepared in two parts. Part 1 attempts to look at CCIR rather broadly, e. g., from t...

This memorandum analyzes the effects of changing the present antenna height restrictions on Class D Citizen's Band operations. The ground wave coverage and potential sky wave interference are compared for monopoles and beam antennas at 20, 40, and 60...

Telecommunications has had and increasingly continues to have a very significant and pervasive impact upon the international relations between the United States and other countries throughout the world. Probably the most important measure of this i...

Coast Guard stations on the West Coast of the United States provide adequate 500 kHz coverage of the ocean within 300 miles of the shore, except possible for some regions around northwest Alaska.

This report documents the initial phase of work done on a study of telecommunications in Alaska in response to the impending sale of the federally owned Alaska Communication System to a commercial operator, RCA Alaska Communications, Inc. The study i...

Modulation techniques for high frequency (HF) data transmission for the Integrated Global Ocean Station System (IGOSS) are discussed. Noncoherent frequency-shift -keying (NCFSK) and time-differential phase-shift -keying (TDPSK) systems are preliminar...

Values of required signal-to-noise ratios are estimated for the following HF communication systems: amplitude-modulation (AM) voice communications systems, noncoherent frequency-shift-keying (NCFSK) radioteletypewriter systems, composite voice and te...

Telecommunications, and hence the demands on the frequency spectrum will continue to grow indefinitely until limited by saturation of all or portions of that spectrum. Only effective planning, based on more knowledge than is now available, will ensur...

This report by the Director of Telecommunications Management on Frequency Management within the Executive Branch of the Government contains an appeal for immediate implementation of a major planning program for the future allocation and use of the ra...

Maps and charts are presented giving the world wide distribution and relative occurrence of ducting and superrefractive gradients of the radio refractive index for the atmospheric layer nearest to the surface. Areas with frequent occurrences of duct...

Central Radio Propagation Laboratory Ionospheric Predictions Based on Numerical Methods of Mapping (formerly CRPL-D series) is described. The Gallet -Jones method of numerical mapping, which is the basis of these predictions, is briefly described. Us...

This report covers only unclassified topics. A substantial portion of the division's work during the quarter was on classified defense programs and included diversion of effort to special scheduled defense projects.

The radar for computing the signal-to-noise ratio of radar echoes from the sun is outlined in this report. The radial distribution of electron density in the corona, the coronal temperature, solar noise, galactic noise, and radar-system parameters a...

Comparison of published results of experimental antenna measurements, particularly gains, reveals apparent discrepancies of the order of one or more decibels. Experimental work at the National Bureau of Standards on scaled model antennas for long-ran...

The special theoretical considerations pertinent to the computation of the phase of the ground wave at low radiofrequencies are discussed. The formulas necessary for the numerical evaluation of the amplitude and phase, and the results of the numerica...

External radio noise levels are presented in the form of an effective antenna noise figure Fa, which is defined as the noise power available from an equivalent lossless antenna relative to kt0b (the thermal noise power available from the passive resi...

The Air Navigation Development Board asked the Central Radio Propagation Laboratory to investigate radio wave propagation in the 960-1600- Mc frequency banned. A primary focus was assessment of the reliability of air-to-grounds communications or ra...

This handbook provides the radio frequency (RF) analyst with the capability to calculate the effects of noise and interference on RF communications receivers. A receiver is modeled as a sequence of modules. Each module has a transfer function that re...

This manual describes the design and use of a software simulator package for HF radios employing FED-STD-1045/MIL-STD-1988-141A Automatic Link Establishment (ALE). This package employs the simulators for narrow-band HF channels and the standard ALE m...

This manual describes the design and use of software simulators for narrow-band HF channels, and for the robust modem specified in FED-STD-1045 and MIL-STD-188-141A. This software was developed by Johnson Research under the sponsorship of the Instit...

A brief overview of nuclear radiation processes is presented. Units of radiation energy and dose are discussed. Interactions of radiation processes with matter are analyzed in order to understand radiation and its energy. Range is discussed in rel...

Accurate laboratory measurement of attenuation rates αx over a range from 0.1 to 10 dB/km at 138 GHz for water vapor (H2O) and its mixtures with air, nitrogen (N2), oxygen (O2), and Argon (Ar) have been performed over a temperatures range from 8 to 4...

This is a final report that describes a project to analyze and evaluate multipath static and dynamic statistics of data recorded in severe ducting and refraction environments. The results shown here were derived by numerical analysis from experiment...

The Technical Subcommittee (TSC) of the lnterdepartment Radio Advisory Committee (IRAC) was tasked to provide NTIA quantitative definitions of terms relating to spectrum efficiency so that NTIA could develop a computer program which uses these TSC de...

Although many listings of submarine telephone cable systems existed prior to 1975, none was sufficiently extensive nor authoritative to serve as a reference work for those interested in the role of submarine telephone cables in the world's telecommun...

Measurements of millimeter wave propagation in urban areas at 9.6, 28.8 and 57.6 GHz, and a determination of signal levels reflected from several building surfaces, were made to study wave propagation characteristics in a city environment. Principal ...

A study accomplished by SRI International under contract with the Commerce Dept., NTIA, in support of work toward developing a U.S. policy for cryptography. It provides an analysis of the policy options based on a projection of evolving I private sec...

This report provides detailed technical, cost and ownership information on all of the commercial underseas telephone cable systems in the world that contains at least one submerged electronic amplifier (repeater) and were in operation as of the end o...

This GitHub repository holds the data associated with NTIA TM-23-566. The data directories follow a format similar to the report with individual directories for the P0N, Q3N, and compound test cases. Each of these directories contains the measured sp...

This GitHub repository contains two datasets collected at the Commerce Department’s Radio Quiet Zone at Table Mountain, Colorado, as well as Hill Air Force Base, Utah: Calibrated airborne field-strength measurements of spatial radiation pattern...

NTIA Technical Report TR-91-272, March 1991, describes measurements taken during an experiment to confirm modeled attenuation and delay rates of dry air throughout the V-band (50–75 GHz). Over 4,000 attenuation values are reported for measurements be...

The Gilbert-Elliot burst error model is a popular and effective tool for treating bursty (non-independent) errors in communication links. This software accompanies the following publication: Pieper J; Voran S, "Relationships between Gilbert-Elliot Bu...

This GitHub repository presents MATLAB®/Octave and C++ implementations of Wideband Audio Waveform Evaluation networks or WAWEnets. This WAWEnets implementation produces one or more speech quality or intelligibility values for each input speech signal...

This document is a user's manual for a program to compute and plot equipotential power flux density contours on the earth's surface from a satellite-borne antenna. The computer output is microfilm plots of the contours on earth maps showing continen...