Ray, https://github.com/chris-elfpen/Teensy4WWVBsdr
73's, John AJ6BC On Sat, Oct 31, 2020, 18:31 <[email protected]> wrote: > Bob, > > "Things already accomplished by Chris in the wwvb AM receiver" > > Is there a link to the AM receiver? Curious as to what that looks like. > > Ray, > AB7HE > > -------- Original Message -------- > Subject: Re: [time-nuts] WWVB teensy BPSK early experiments > From: Bob kb8tq <[email protected]> > Date: Sat, October 31, 2020 11:42 am > To: Discussion of precise time and frequency measurement > <[email protected]> > > Hi > > …..errr….. > > Can you pull the clock oscillator off the Teensy board? (Yes, the > soldering > iron would be involved). > > Will the clock input to the MCU accept something like 10 MHz? If so > solder > on a cable …. > > At that point whatever the Teeny does is locked to the 10 MHz. If that > comes > from one of the $3 eBay OCXO’s, steer that with a DAC output … now > you > have a WWVB GPSDO. > > Indeed, if the Teensy needs 28 MHz, then the OCXO will not be quite as > cheap. > > Bob > > > On Oct 31, 2020, at 1:47 PM, paul swed <[email protected]> wrote: > > > > Hello to the group. Wanted to update the everyone thats interested in > > what I have learned so far on the Teensy and audio codec. No complete > > solution yet. Much of my experimentation and knowledge has come from > Frank > > and Chris, who built the complete wwvb AM time receiver. In addition > > and important is Johns KD2DB BPSK receiver. There is a reason this > matters. > > > > The teensy combination is powerful and somewhat easy to use. (Has to be > for > > me). So over the week or so it's been getting used to the audio libraries > > and how pieces are connected in software and then seeing the results. All > > of the base experiments worked very quickly. Simple things like signal > > generators, multipliers and filters. Things already accomplished by Chris > > in the wwvb AM receiver. > > > > But the question really is what to accomplish? > > If its the wwvb bpsk timecode. Simply buy an ES100 and be done. > > > > The interest that I have is a locked reference. Minimizing soldering and > > construction. This is the point things get interesting. > > A NCO can be created in Teensy but it tends to be low frequency and a > > multiple of 60 KHz. Stability sort of isn't. But if it could be created > > then a complete frequency reference in the teensy could be accomplished. > > That makes for a heck of a low power receiver 1 watt, inexpensive, and > > little soldering. > > The above path literally follows the old Spectracoms and Truetime direct > > conversion receivers. > > Have to look at their schematics because they do lock a useful reference. > > But that means something external has to come into the teensy. Get the > > soldering iron hot. > > > > The other approach is essentially Johns KD2BD receiver in software with > an > > external reference chain delivering 50KHz and 10 KHz to the teensy. Well > > this is getting ugly now because that external chain is made up of a > > classical divider 10 MHz to 50 KHz etc. But does give a very nicely > locked > > useful wwvb reference. Its really a hybrid because it significantly > reduces > > the soldering required in a true KD2BD receiver but isn't the pure in > > a chip solution. > > > > All of this is just for fun because the fact is the GPDSOs we use are > > better. > > If a receiver is built a natural by-product is the time message. Its just > > not my focus or interest. > > Much more to learn. > > > > Next steps > > Start to reuse the wwvb teensy AM receiver. > > Chop out all of the display software. Its all very nice but for me at > this > > stage gets in the way of understanding things. > > > > With respect to I&Q generation several suggestions have been made. But > the > > teensy supports multiple multipliers. Sort of thinking, use the sine > > wave oscillator and add a 90 degree delay to a second path to a second > > multiplier. An alternative inject the delay in the wwvb signal also. How > > fine a delay is a serious question. > > Much to learn and potholes to fall into. > > Regards > > Paul > > WB8TSL > > _______________________________________________ > > 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. > > _______________________________________________ > 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.
