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Re: Phil's FEC decoder, bplay and built in microphone

Achim Vollhardt wrote:

> Mixer setting was Mic input (used kmix) , sensitivity has no influence
> on the Es/No 60 reading. Mic responds: if I set sensitivity and speakers
> to high, I get acoustic feedback.

This sounds suspiciously like you don't have the microphone input 
selected in your mixer panel and you're feeding silence to my 
demodulator. Sound interfaces vary, but they usually have separate 
"record" and "play" busses. Typically you have to push a button to 
select an input (microphone, line, CD, etc) to be connected to the 
record bus, and this is distinct from monitoring via the play bus the 
various inputs with the various mixer sliders (volume controls). So the 
fact that you get acoustic feedback simply means that you have the 
microphone connected to the play bus; it doesn't mean you're also 
feeding it to the A/D converter.

Sometimes there is a mixer slider that lets you monitor the record bus 
through the play bus. Try turning that up and all the other sliders 
down, hit the record select button for the microphone input, and you 
should hear audio on the speaker *and* it should reach the A/D converter.

Before trying to run dpsk_demod, try to record and play back some audio 
  using brec and bplay, or equivalent programs.


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