[RTTY] [CQ-Contest] RTTY contest software

[Jerry Flanders]

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