[time-nuts] WWVB PM Time Questions

[Lester Veenstra]

Software Costas, see MatLab:
https://www.mathworks.com/matlabcentral/fileexchange/16744-demodulating-a-bp
sk-using-costas-loop?s_tid=FX_rc2_behav


Lester B Veenstra  K1YCM  MØYCM  W8YCM   6Y6Y
lester at veenstras.com

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-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces at lists.febo.com] On Behalf Of paul
swed
Sent: Wednesday, July 22, 2020 1:26 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] WWVB PM Time Questions

The KD2BD receiver is a costas loop.
So look at that and you have the answer. It does not decode the BPSK data
though. Thats quite a project all by itself.
Regards
Paul

On Wed, Jul 22, 2020 at 10:42 AM Rodger via time-nuts <
time-nuts at lists.febo.com> 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.  It has also been suggested
that
> a WWVB SDR wouldn't be too difficult to build and would open up lots of
> possibilities.  Unfortunately, I don't have a clue where to begin with
> that.
> Maybe somebody with some SDR experience can chime in.
>
> Re your comment about $30 BPSK clocks.  The only clock I'm aware of that
> uses the BPSK is the Lacrosse Ultratomic.  Are you aware of any others?
>
> Thanks,
>
> Rodger
>
> -----Original Message-----
> From: time-nuts <time-nuts-bounces at lists.febo.com> On Behalf Of
> rcbuck at atcelectronics.com
> Sent: Tuesday, July 21, 2020 11:52 PM
> To: Discussion of precise time and frequency measurement
> <time-nuts at lists.febo.com>
> Subject: Re: [time-nuts] WWVB PM Time Questions
>
> Paul, thanks for the suggestions. The top of the minute is a good idea.
> Since the first second is part of the sync pattern it will always be 0 and
> the phase would be 0. A differential opamp with one input from WWVB and
the
> other from the local source fed to the STM32 would tell if the signals
were
> in phase. A single gate inverter controlled by the STM32 could be used to
> invert the local source if necessary.
>
> I have worked with the Bluepill for the last year on a few small projects.
> The most complex one (which isn't really complex) was to control two
> stepper
> motors. I really like the boards and you can't beat the prices. I don't
use
> the bootloader so I have no experience with it.
>
> Dana, I looked at the Costas loop and had sort of ruled it out. I may take
> another look at it as I get further into the project. I will probably use
a
> 15.360 MHz oscillator and divide by 256 to get the 60 kHz local source.
> Once
> I get the front end working I will be able to start some "real" testing.
>
> Suggestions from others are welcome.
>
> Ray,
> AB7HE
>
>
>
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