At 18:32 10/22/2006, Kok Chen wrote:... With
>cocoaModem, I had implemented 9 separate FSK demodulators to watch a
>single signal -- each demodulator has a slightly different relative
>mark/space delay and a different ATC (automatic threshold correction
>in the slicer) time constant. The nine outputs then goes through a
>soft decision logic to print a single character to the screen --
Sounds very promising - we need to get you to start working on the
Windows platform ;-)
... you also don't want to reduce the audio gain of a
>software modem to the point where you are working with just the least
>significant 8 or 9 bits of your A/D converter - you will not beat an
>ST-8000's 85 dB of dynamic range that way. ...
I recently learned that sound cards vary widely in regard to sampling
speed capability as well as bit depth when I was studying current
PC-based SDR techniques. Are there any modem performance advantages
to be gained in using a high end ($150 - $300) sound card like the
M-Audio Delta 44 or the Edirol FA-66, which are being touted as
optimum for the SDR-1000 transceiver? If not, might there be an
advantage in using a software modem specifically written to take
advantage of these cards' superior performance?
Jerry W4UK
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