Hello Time Nuts, I have a question -
Has anyone been successful getting WWVB to decode using the example for DCF77 and making the changes for WWVB? Chris has his own approach - it's interesting - but on my setup at least I haven't been successful with it - maybe it's my antenna - not sure just yet. Also - my screen eventually 'whites-out' after running that for a while - meaning - the screen goes completely white and I don't know what's doing that yet - I suppose it's a bug of some sort. But, with the DCF77 approach - it appears to identify bits OK - with the code having only minimal changes - so I'd like to go down that path. Note - I have a fork here - but it's debug - and not sure it's worth anything other than looking at some of the data that's being dumped. https://github.com/jwestmoreland/Teensy-DCF77 For DC7FF - the AM is just 0.2ms (1) and 0.1ms (0) with no AM at the minute marker, but WWVB is a little more complicated - 0.2ms (0), 0.5ms (1), and 0.8 ms (Marker) - 2 consecutive markers mark the end of current minute/beginning of next minute. The DCF77 code seems to take some advantage of the signal level/timing and the dimensions of the TFT display for displaying the signaling - at least that's what it appears to me right now unless I'm looking at this wrong - I guess that isn't a big deal until you try to deal with the marker timing for WWVB - of course I could be looking at this wrong right now too. Maybe trying something like the Goertzel algorithm like KE9NS has done in his work with WWV is worth taking a look at too with this setup. 73's, John AJ6BC On Sun, Nov 1, 2020 at 10:50 AM Mike Feher <mfe...@eozinc.com> wrote: > Too bad I am an old retired hardware engineer and know nothing about these > new SW controlled devices. Have Fun - Regards - Mike > > Mike B. Feher, N4FS > 89 Arnold Blvd. > Howell NJ 07731 > 848-245-9115 > > -----Original Message----- > From: time-nuts <time-nuts-boun...@lists.febo.com> On Behalf Of paul swed > Sent: Sunday, November 1, 2020 12:48 PM > To: Discussion of precise time and frequency measurement < > time-nuts@lists.febo.com> > Subject: Re: [time-nuts] WWVB teensy BPSK early experiments > > John sent the link on the teensy wwvb AM receiver. It can easily be > shifted to other frequencies. Using the work Frank dcf77 and then Chris > wwvb did with the PJRC audio design tool gives quite a bit of insight to > the work that was done. > The system assumes a sample rate of 192Khz. That limits the receive range > to about 98KHz. > I have not been able to confirm the rate I am using is 192Khz and when the > set command is used its not recognized. So somethings up. > The design Chris has essentially is a microphone input with some 38 db of > gain feeding a bandpass filter around 60 KHz to a multiplier (RF mixer) > then a low pass filter. Chris and Franks design is much more than these few > words with spectrum display, signal level, and AGC. > So without any effort the frontend solution is sitting in the teensy that > cuts out a bunch of typical wiring. Granted its not as tight as discrete > components can be. But its a chunk of software code. No digi key orders for > L & Cs... :-) The output of the chain is 600 Hz audio that does contain the > phase changes. > > But the trick is creating the true I & Q channels. Not an issue to add a > second multiplier and chain did that last night. But at someplace a 90 > degree phase change or delay needs to occur. > Or as suggested a hilbert transform. > Regards > Paul > WB8TSL > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.