[email protected] said: > I built a small CMOS divider connected to the UT+ 1 PPS output...
What do you mean by "CMOS"? Old 4000 series parts or HC or ... ? > Here's the problem: my counts vary significantly (+/- 10000 or more) from > cycle to cycle, which is much higher than expected based on 50 nS period > uncertainty of the 1 PPS ... Do you have a scope? I'd check the triggering levels. Your counter may be setup to just barely trigger on your CMOS signal. Your CMOS divider may have troubles triggering on the output of the UT+. One experiment would be to connect the PPS directly to the gate input on your counter. That won't tell you your crystal frequency, but if things work, it should get a consistent count each pulse. If you have a digital scope, you can trigger on the PPS and look at the PPS in delay by a second mode. (That tells you the accuracy of the crystal in your scope.) If the PPS delayed by a second isn't stable, you know the UT+ is confused. -- These are my opinions. I hate spam. _______________________________________________ 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.
