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 <[email protected]> On Behalf Of [email protected] Sent: Tuesday, July 21, 2020 11:52 PM To: Discussion of precise time and frequency measurement <[email protected]> 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 _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
