> I am in the middle of the design of a micro which uses a 10MHz crystal > to provide a digital clock, but the time is kept in line via GPS using a > 1pps NCO, which is steered digitally, rather than altering the 10MHz > oscillator in GPSDO fashion. > > The plan was to provide two outputs (biphase) at 1pps to drive slave > clocks, but in the light of the notes from Brooke and Chuck, I would be > better off just providing a single output, and use a series cacacitor. > > Chuck, I would expect that the 1pps would need to be about 50% duty > cycle, or at least have a pulse width of 100ms or so. I can imagine a > clock driven from 1pps with a low duty cycle would sound quite > different. > > 73, > Murray ZL1BPU
50% duty cycle is way overkill, perhaps even harmful. In the 'scope traces below you can see the IC generates just 50 ms biphase pulses every second. That's 1/20, or 5% duty cycle. http://www.leapsecond.com/pages/32kHz/ /tvb _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.