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How to Evaluate The Voice Quality of ATAs

2007-7-10

Voice quality is one of the most important aspects of voice telecommunications. There are many factors that affect voice quality. There are there key parameters that characterize it: clarity, delay, and echo.

Voice Clarity

Clarity refers to the clearness or fidelity of voice as it is reproduced by a network and perceived by a listener. Factors that influence the clarity of voice on a communications networks are: speech encode and decode; packet loss; packet jitter; background noise; voice activity detectors.
Many methods could be used to measure voice clarity, include Mean Opinion Scoring(MOS)，Perceptual Analysis Measurement System(PAMS)，Perceptual Evaluation of Speech Quality(PESQ)。They come from different standard.

Next we introduce a voice clarity test using Agilent Voice Quality Tester(VQT).

The above graph is the test environment and G.711A, G.711U and G.729 PAMS score of GIX100 for 8 hours long run which were tested by Agilent Voice Quality Tester (VQT).

In 8 hours continuing long run test, The voice quality of GIX100 is stable and as good as the beginning of getting through not matter using G.711A,G.711U or G.729 codec after a long run call lasted for 8 hours. And in the telecom carrier requirement the standard voice quality for G.729 and G.711 PAMS score should keep above 3.6 and 4.0.