Institute for Telecommunication Sciences
the research laboratory of the National Telecommunications and Information Administration

Edmund A. Quincy; Robert J. Achatz; Michael G. Cotton; Michael P. Roadifer; Jeanne M. Ratzloff

Abstract: 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 frequency-selective multipath and non-Gaussian noise. During radio link signal simulation an error sequence, determined from a comparison of transmitted and received bits, was collected. Next digitized speech and image information was distorted by the error sequence. Last, the quality of the distorted speech and image information was subjectively evaluated. This process was repeated for a large number of interference conditions. The same process can be used to show how multipath and non-Gaussian noise affects speech and image quality. Other wireless applications such as personal communications services and wireless local area networks can be analyzed in the same way using radio channel measurements and models made by the Institute for Telecommunication Sciences.

Keywords: multipath; interference; non-Gaussian noise; digital modulation; radio channel; speech coding; speech quality; radio link; bit error; image coding; image quality; software simulation.


To request a reprint of this report, contact:

Lilli Segre, Publications Officer
Institute for Telecommunication Sciences
(303) 497-3572
lsegre@ntia.doc.gov

For technical information concerning this report, contact:

Robert J. Achatz
Institute for Telecommunication Sciences
(303) 497-3498
rachatz@ntia.doc.gov


Disclaimer: Certain commercial equipment, components, and software may be identified in this report to specify adequately the technical aspects of the reported results. In no case does such identification imply recommendation or endorsement by the National Telecommunications and Information Administration, nor does it imply that the equipment or software identified is necessarily the best available for the particular application or uses.

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