Have to look at what oscillators and crystals I have then a divide. Thats old style and most likely the junk box has everything. Have to look in my box of tricks as I built several chains for the de-psk-er experiments. Have to agree on the micro the chronverter uses a pIC 12F64 as I recall and it has quite a nice set of dividers in it. Just not an external crystal input so a better oscillator can be used. Getting lazy these days. I have some number of tcxos from a company called vectron. Several cards of each. Can't imagine how I came by those. :-) Believe the lowest freq was 12 MHz. Regards Paul.
On Sat, Aug 25, 2018 at 8:07 PM, Bob kb8tq <[email protected]> wrote: > 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. > _______________________________________________ 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.
