[time-nuts] WWVB BPSK Receiver Project?

[Peter Monta]

> Many A/D converter systems use a sample and hold before the A/D converter.
> If you do the same before your sound card (your A/D converter) and drive the S&H with an audio output from your sound
> card, say at 6.1 kHz you would get a 1 kHz signal into your sound card to process. You can call it under sampling
> aliasing or whatever.

Yes, this would work, but instantaneous sampling would tend to alias
in many harmonics, requiring good prefiltering at RF (if you can call
60 kHz RF).  Just as easy would be a mixer from CMOS switches, driven
say at 50 kHz to get 10 kHz into the sound card.

The WWVB signal apparently has a double-sided bandwidth of about 1200
Hz (not clear from the paper if that means 3 dB bandwidth or something
else).  To get all of the signal something like 2 or 3 kHz might be
safest, requiring an IF of several kHz at least.

Cheers,
Peter