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

Christopher Redding; Nicholas DeMinco; Jeanne Lindner

Abstract: 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 standardized (and patented) objective voice quality estimation algorithm developed by the Institute for Telecommunication Sciences (ITS). This method determines an auditory distance (AD) and converts it to a finite scale that can be related to the mean opinion score (MOS) scale commonly used in subjective voice quality tests. This testing establishes the feasibility (from a voice quality perspective) of using vocoders in a tandem configuration in order to relay voice communications between disparate systems.

Keywords: communications; mean opinion score; vocoder; speech codec; tandem; voice quality of service; objective testing; logistic auditory distance; subjective testing; perceived speech quality


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:

Christopher Redding
Institute for Telecommunication Sciences
(303) 497-3104
credding@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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