BR> Well, what I had in mind was to digitize a voice signal and send it over
 BR> a radio link and then recove the audio at the other end less the static.
That's done with broadcast STL's and spread spectrum RPU's regularly.  It can 
also be done via POTS or ISDN, with various quality levels of good to 
excellent.   
 BR> The fidelity required for a voice signal might be a little less that
 BR> what you calculated but it doen't look like it would help enough to make
 BR> this feasable on the radio since the current BPS rates on radio (to the
 BR> best of my knowlege) are no where near this high.
You can get a low distortion, moderately high sn (80 dB), 8 kHz response 
audio signal down a POTS line using a CCS/Musicam Fieldfone.  That uses a 
modified Musicam compression algorithm which is ISO MPEG L-II decode 
compatible, and feeds it to a V.34 modem.  Cost of the encode side is about 
$4,000, with the decode end potentially cheaper and allowing any standard 
MPEG L-II decoder.  
Expect 20 kHz response 90+ dB sn stereo audio through an ISDN B channel (64 
kbps synchronous, no start/stop bits) with some coding artifacts.  The coding 
artifacts drop to minimal with a bonded ISDN B pair at 128 kbps, and become 
nearly imperceptible and allow recoding overhead at 256 kbps.  Expect a cost 
of about $5,000 per site.  
Terry
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