[dsp] Analog front end design

[David Willmore]

> I was looking at a nice dual-channel 16-bit CODEC from ADI (AD73322L), but
> the problem I ran into with that chip is that it has a limited selection of
> sample rates, and they're not baud rate multiples.  Maybe the clock could be
> changed, but I don't know enough about sigma-delta ADC design to know if
> that's really a good idea.  Another possibility is to use the MCU's on-board
> ADC, but it would require the addition of a buffer and it'll only do 10 bits
> of resolution.  I'm not sure that'll give enough dynamic range, especially
> if I need to do much filtering in software.

What's baud rate got to do with it? :)

1200 baud AFSK decode:
AD > complex mix with 1700 Hz tone > 600 Hz LPF > ArcTan > clock recovery/data decode

Good to hear from you, Scott.

Cheers,
David