Hi A pretty simple modest Q tuned circuit on the output of a gate will turn the square wave into a sine. Not much to it since there are a lot of power supply components out there that work fine at 60 KHz. In order to get a stable 60KHz, a divider is the way to go. I’d probably use one that’s built into an MCU as part of a timer or something similar.
Bob > On Aug 25, 2018, at 7:00 PM, paul swed <[email protected]> wrote: > > Bob The generator sig is 60 Khz sinewave.but as a I build up a divider > chain and such your idea makes great sense. > Then filter to 60 KHz. > But I see the issue with the Chronverter carrier its 120-150 Hz high. > Bounces around a fair amount. > There could be a secondary issue in that the carrier may not actually be > phase stable. > It really doesn't matter as for the Truetimes and Spectracoms its simply > not good enough. > I still need to try the cheapy clocks as that is what it was intended for. > Not throwing stones as so much of what it does saves me a bunch of coding > and doing exactly what Dave did. > Regards > Paul > WB8TSL > > On Sat, Aug 25, 2018 at 5:31 PM, Bob kb8tq <[email protected]> wrote: > >> Hi >> >> You can do the 14 db deep modulation with a tristate gate and a pair of >> resistors. >> Ground the input and feed the “modulation” signal to the tristate control. >> >> Bob >> >>> On Aug 25, 2018, at 4:35 PM, paul swed <[email protected]> wrote: >>> >>> From the earlier threads OOK modulation does not work for high end clocks >>> like spectracoms and truetimes. Have not tried it on the cheapy clocks >> yet. >>> >>> I added an external modulator. A dg419 analog switch and then with a few >>> resistors added DC offset and anttenuation so that the carrier drops by >> -14 >>> db per the wwvb spec. The logic control is driven from the chronverter >> and >>> it totally works. Spectracom Netclock 2 locked up in the normal time. >>> There are far better modern single supply analog gates that will work. >> Just >>> did not have any. >>> >>> The 60 KHz carrier is supplied by a fluke 6060 generator. This eliminates >>> any chance of being off frequency and is not the long term answer. >>> >>> The chronverter actually uses a dallas semiconductor clock chip thats >>> reasonably accurate.(dangerous to say on time-nuts) So that even if you >> do >>> not add the GPS receiver it will run quite some time correctly after >>> setting the time. >>> >>> Chronverter draws 6 ma from a 5 V supply. I always like low power. >>> >>> All in all a very nice answer to what do we do if WWVB goes away. >>> As mentioned it handles timezones and DST and you can change DST if those >>> silly politicians screw with it again. >>> >>> Speculation >>> The chronverter actually puts out carriers for the popular LF stations >>> along with the time codes for them. >>> >>> Though the modulator allows quality clocks to lock I speculate the >>> frequency from the chronverter is not tight enough. All of these clocks >>> have very sharp crystal filters in them. 10 Hz. Plan to measure the >> output >>> of the chronverter see what the 60 KHz is actually at. Though listening >> on >>> a HP3586 receiver it appears pretty close to frequency maybe its just not >>> good enough. Or the fact is OOK modulation does not work because it gaps >>> the PLL in these clocks. >>> >>> Next steps >>> >>> - Determine and lay to rest the OOK/need for external modulator. >>> - Power amplifier and loopstick transmitting antenna staying at or >> below >>> 30uv@30 meters. >>> - Integrate a neo6 GPS receiver in. (Seriously easy) >>> - >>> - Box it up. >>> >>> Have my eye on one of the Truetime DC468 units and the classy panelplex >>> display. >>> >>> Hope this helps those of you concerned with what to do should WWVB go >> away. >>> 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.
