Divide 10 MHz by 250 to get 40 kHz, to be within range of the clock's logic, then use a presettable counter loaded by the 1 PPS to count off 32768 clocks per second.
David McGaw At 11:30 AM 7/23/2008, you wrote: > I was faced with this problem a few years ago, too. > I essentially followed John's solution, but used the 1pps GPS pulse as > the PLL reference. > I then used the 32.768K vco output to injection-lock the 32.768K > crystal on the LCD clock. > Much to my surprise, it worked quite well. And, as pointed out already, > jitter isn't an issue for this application. >Bill Ezell >---------- >They said 'Windows or better' >so I used Linux. > > John Franke wrote: > >The only thing that comes to mind is to divide the 10 MHz by 2500000 >(5x5x100000) and then use a phase locked loop to multiply by 8192. Of >course the PLL would best control a varactor with a clock crystal vice >controlling an RC oscillator. Other divisor multiplier pairs are: >1250000/4096, 625000/2048, 312500/1024, 156250/512, and 78125/256. > >John WA4WDL > >----- Original Message ----- >From: "Max Skop" [1]<[EMAIL PROTECTED]> >To: [2]<[email protected]> >Sent: Wednesday, July 23, 2008 10:09 AM >Subject: [time-nuts] How to get 32.768KHz from 10MHz. > > > >How does one get a 32.768KHz signal from our 10MHz reference. >There does not appear to be a nice divide ratio to do this. >With a locked 32.768KHz signal one could lock the oscillator of any of >the cheap (low cost) LCD clocks that are available with nice big digits, >temperature sensors and calendars, etc. >Any suggestions on how to do it?? > >Regards >Max > >ps. I got sucked in good. Six months ago all I had was an HP 10811 and now >I have another crystal oscillator, two rubidiums and a Trimble GPS. >_______________________________________________ >time-nuts mailing list -- [EMAIL PROTECTED] >To unsubscribe, go to >[4]https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. > > > >_______________________________________________ >time-nuts mailing list -- [EMAIL PROTECTED] >To unsubscribe, go to >[6]https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. > >References > > 1. mailto:[EMAIL PROTECTED] > 2. mailto:[email protected] > 3. mailto:[email protected] > 4. https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > 5. mailto:[email protected] > 6. https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >_______________________________________________ >time-nuts mailing list -- [email protected] >To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
