[time-nuts] WWVB BPSK Receiver Project? (fwd)

Poul-Henning Kamp phk at phk.freebsd.dk
Sat Mar 17 07:20:24 UTC 2012


In message <Pine.LNX.4.64.1203170042050.2576 at tesla>, Marek Peca writes:

>My only argument against your versatile and well-performing solution is 
>that it is a little bit overkill.

As if running a handfull precision oscillators just for fun isn't
"overkill" also ? :-)

>In other words, it would be certainly better to buy USRP N210,

Actually that would be a very idea, because you cannot get rid of
the down-sampler in the USRP and that would make Loran-C reception
very tricky to implement.

>My point is to do something with relevant performance wrt. <10kHz wide 
>LF signals.

The crucial question is if your are doing timenuttery or radionuttery.

If you are doing timenuttery, you want you ADC synchronized to your
OCXO/Rb/Cs or whatever you have, and you don't want to have to deal
with getting your IF frequency locked too.

Soundcards use inconvenient frequencies and are seldom built to take
an external clock signal.

>The useful bandwidth of LF to HF radio is about 9kHz, 

You need more than 25kHz for good Loran-C

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.




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