[time-nuts] WWVB PM Time Questions

[Richard (Rick) Karlquist]

On 7/22/2020 7:35 AM, Rodger via time-nuts wrote:
> Hey Ray,
> 
> Paul and I have a nice piece of code that generates the WWVB BPSK bit stream
> using an Arduino and a ublox GPS module. (total cost under $30)  You could
> use this as a WWVB emulator while you're working on your code.  Sorry, I
> can't really help with your question about demodulating the WWVB BPSK but
> the Costas loop sounds like the way to go.  
> 
> Rodger
> 

A long time ago, I built a demodulator for some weather satellite
that used BPSK that used a Costas loop driving a VCXO.  I had
never built a Costas loop before, but I have to say that it was
quite straightforward and it totally worked as advertised.
The loop requires an analog multiplier, and I didn't have much
trouble sourcing it.  Fast forward to today, and the same small
number of multipliers are still available, they just cost a lot.

For 60 kHz, of course, you will want to divide down a VCXO that is
at a reasonable frequency for such.

Rick N6RK