[time-nuts] WWVB BPSK Receiver Project?
Marek Peca
marek at duch.cz
Thu Mar 15 10:58:49 UTC 2012
> I know I am not one of the good-ole-boys here but I'd say go 100% SDR
> with your PC without an external A/D converter. Ok, how would you do
> this? You use under sampling. 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.
Unfortunately, this works only with a few types of sound cards. Last
several years, most of PC audio cards use sigma-delta ADCs and there is no
way to get quality undersampling. Tried it. I can not tell there was no
signal -- there were really some carriers mirrors, but on odd frequencies
and largely attenuated.
Greetings,
Marek
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