Specifications

AN93
Rev. 0.9 195
Audio Playback and Analysis
An analysis software package that is capable of
showing the spectral contents as they change over time
is recommended. The two most widely-used ones are
Adobe Audition, a commercial product, and Wavesurfer,
which is a free, open-source product. Below are two
displays showing the results of recording a good V.22
transaction. It is important to know that we need to
examine the signal both in the time domain and the
frequency domain, with the frequency domain being a
much more useful view. The graphs below show time on
the horizontal axis and either wave energy in dB or
Frequency in Hz on the vertical scale. In the case of the
frequency display, the color of the wave indicates the
energy at that combination of elapsed time and
frequency. The color scheme is programmable. It is
typical in the temporal view to see a dc offset until one
applies a high-pass filter (a step that is rarely
necessary).
Figure 58. Adobe Audition Temporal View of a Good V.22 Transaction