Hi, For PPS I always set the trigger by hand as I don't trust autotriggers to do it right. Wonders when I will see one that does.
Cheers, Magnus <div>-------- Originalmeddelande --------</div><div>Från: Bob Camp <[email protected]> </div><div>Datum:16-02-2014 23:07 (GMT+01:00) </div><div>Till: Discussion of precise time and frequency measurement <[email protected]> </div><div>Rubrik: Re: [time-nuts] Measuring 1 PPS with an HP 5335A </div><div> </div>Hi If you have a 50/50 duty cycle 1 pps, it’s going to work with a lot of settings. With a narrow (say 10us wide) pulse, most of the counters have auto trigger issues. If it’s already known to be reading nutty, trigger is a good place to start looking. Bob On Feb 16, 2014, at 4:29 PM, Paul <[email protected]> wrote: > On Sun, Feb 16, 2014 at 2:33 PM, Bob Camp <[email protected]> wrote: > >> On all these counters, you need to switch to DC input for 1 pps signals. >> You also need to manualy set the trigger level to something like +1.5V. > > > I can't believe I'm disagreeing with Bob Camp but this is not my > experience. 99.9% of the time preset trigger works fine and I think you > should start with that. AC coupling almost always works and is sometimes > required (with the Rb I think). > > I have a 5335A (w/ opt 010+040) and have measured 1PPS on my PRS-10, Fury, > Firefly and random GPS parts. If the trigger light is not flashing at 1 Hz > the only thing I've ever had to do is toggle AC coupling or enable 1PPS > output on the device (or plug it in). Sometimes increasing the gate time > tidies up the display. > _______________________________________________ > 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. _______________________________________________ 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.
