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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...

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 th...

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 ...

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...

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...

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, impul...

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...

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...

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...

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...

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...

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...

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 fo...

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 electrica...

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...

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 analy...

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...