User's Manual Part 2

Nomad User’s Manual Appendix D – PESQ Tools GUI Case Study

Appendix D – PESQ Tools GUI Case Study

The PESQ Tools GUI is available for Nomad users wishing to perform advanced analysis of any

waveform captured during Voice Quality testing and scored using PESQ. Basic operation of the

PESQ Tools GUI is described in Section 8.7.

The PESQ Tools GUI can assist in the identification of issues that contribute to low MOS such as

background noise and speech clipping. This appendix presents a case study illustrating how the

PESQ Tools GUI may be used to identify these types of issues in a test file exhibiting low MOS

results.

To start, the Reference Waveform, Reference Surface and Reference Spectrogram tabs display

what the test waveform should look like. The Degraded Waveform, Degraded Surface and

Degraded Spectrogram tabs display what the waveform actually looks like. Sample waveforms

with low MOS results will contain visible differences from the reference images.

In this example, the Reference Waveform is free of noise during periods without speech while the

Degraded Waveform exhibits a constant buzzing during “quiet” periods:

Figure D-1 - Reference Waveform

Figure D-2 - Degraded Waveform

Not only is this buzzing visible in the Degraded Waveform image, it is audible in the .WAV file. Use

the Play button to listen to the effect of the buzzing on the speech sample.