Thread: Receiving WWVB
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Old October 4th 03, 12:16 AM
Bill Janssen
 
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Joel Kolstad wrote:

I've been thinking about building a WWVB (time code on 60kHz) receiver, and
wanted to get some suggestions for the architecture. Poking around the web
some, I did find one receiver where the guy built a synchronous detector
using a PLL and VCXO to phase-lock to the 60kHz carrier. Nice idea --
especially since he wanted the 60kHz carrier as a synchronization signal.
However, I just want the time data... so... wouldn't it be easier to build a
mixer at, e.g., 59kHz and then use an envelope detector to get a loud/quiet
audible (1kHz) tone (WWVB reduces power by 10dB to signify 0 bits in its
time code)? It seems to me that this approach avoids the need for the PLL
and VCXO, which is a nice 'reduction' in complexity. Also, since I'll have
a microcontroller around to decode the time code anyway, it can easily
generate the 59kHz signal.

Thanks,
---Joel Kolstad


I think you will need a receiver with a narrow band pass. The phase locked
scheme can help you get a very narrow band pass.

Another arrangement is use the 1 Khz as you planned and use a FFT program to
get the signal out of the noise..

And maybe, at your location, the signal is strong enough that my concerns
do not apply.

Bill K7NOM