Hi Are we talking about steps between adjacent pps outputs or the relation of the pps output to correct GPS time? They are two very different things. I can put out twenty pulses that are each 50 ns to fast and be 1 us off relative to the correct time.
Bob -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of David J Taylor Sent: Thursday, March 14, 2013 2:57 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Is possible precise 1pps? From: David [] This brings up something that I have wondered about for a while. The Garmin GPS18x (and many other receivers) specify the PPS output as within 1uS but does that mean it wanders around over say 12 or 24 hours within 1uS of GPS Time or does it mean something else? I can easily see the granularity of the PPS output but that is obviously not what the specification refers to. I guess I need to pickup a real timing receiver or good oscillator to run a comparison with to see what is going on. ============================= David, I haven't looked often, or in great detail, or logged results, but my 18x and 18x LVC seem to be very similar in its offset from the rest such as U-blox 6M, 6T, Sure, Adafruit etc. I.e. well within 100 ns. Causal test, others may have measured more accurately. I've not seen any 1 microsecond steps. Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: [email protected] _______________________________________________ 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.
