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FAA20 Embedded NEXCOM Vocoder

Board Manual

This manual has been prepared for the Federal Aviation Administration.

FA100-00107 (March 2004) – Rev 1.0.0 Page 46

7.2 Test and Integration Tools

The FAA20 includes three categories of test and integration tools:

• Audio Tools

• Nibble Tools

• PCM Tools

7.2.1 Audio Tools

There are three types of audio test and integration tools:

• Mixer/Router

• Tone Generator

• Signal Analysis Tools

The mixer and router (see the MIX/ROUTE commands) can be used to

insert loopbacks in the voice processing flow and thus isolate configuration

and timing setup problems.

The tone generator (see the TONE command) can be used to isolate

problems to the transmit or receive path for as specific voice port. Since

the tone generator internally sourced, it is usually used to verify the function

of an output port.

The signal analysis tools, while powerful, are rarely needed to isolate

FAA20 integration problems; however, the tools can provide additional

information. Typically, these tools are used by the factory to isolate

incorrect filter components in the analog front end.

There are three signal analysis tools: a tone detector (TEST TONDET), a

spectrum analyzer (TEST FFT), and a sweep generator/detector (TEST

SWEEP). All three tools use a 64-point fast fourier transform (FFT)

algorithm for frequency analysis. The FAA20 uses the mixer COM port to

collect data needed for analysis because of its large data capacity. Thus,

to use these tools, the signal to be evaluated must be mixed (routed) to the

COM port. The sweep generator has an additional routing requirement. In

order to test the audio front end, it requires that the tone generator be

routed to the AUD mixer port. Figure 21 is a command example illustrating

the use of the sweep generator.

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Digital Voice Systems VC-20-ATC-10B Spezifikationen Seite 52