4. With 1PPS you probably want to run it in time-interval mode and measure the phase difference of two clocks: have it start on CH1 with (say) the 1PPS from your microsemi, and stop on CH2 with your uBlox. You should still have it on ext-REF with 10MHz from the Rb-clock.
gate time refers to measurements in frequency counter mode, usually not used with 1PPS signals. On Mon, May 2, 2016 at 2:09 PM, Peter Membrey <pe...@membrey.hk> wrote: > Hi guys, > > I'm looking to measure and characterize the 1PPS output of a uBlox MAX M6Q > using a Keysight 53230A. Specifically, I'm mostly interested in the period > of the signal, how close it is to exactly 1Hz and how that signal changes > over time. > > The Keysight is using the 10Mhz output of a SRS FS-725 Rubidium Frequency > Reference (which is being disciplined by a PPS from a microsemi S600 GPS) > as an external reference. > > I've currently got the channel configured as follows: > > * DC > * 50Ohm > * Bandwidth filter enabled > > The default gate time is 100ms, which if I leave it configured for that, > it will never show a reading. I can get it to start giving a reading if I > set the gate time to 3 seconds but for reliable readings, I need to set it > to at least 5 seconds. > > So, here's my questions: > > 1. I would like to capture the period of each pulse - is this doable with > my set up? > 2. What does gate time actually mean? I've read a number of descriptions, > but I'm still not 100% clear on what it means in this context and what > impact it has > 3. How exactly does the gate time work in this case? I mean if it captures > data over 5 seconds and gives one reading - what actually is that reading? > An average? One of the samples? > 4. Should I be doing anything differently? > > Ideally, what I'd like to do is capture the period of each pulse > individually so that I can do an Allan variance on the data over a period > of time. > > I've googled around and I've read numerous guides, but they mostly seem to > cover faster signals (like 10Mhz sine wave) rather than the much slower > PPS. I asked a very similar question on the EEVBlog forum, and the > suggestion was to use time-stamp capture with the rise time, but > unfortunately, it never seems to see the signal, even though the gate > indicator flashes every second. > > Thanks in advance for any advice or guidance! > > Kind Regards, > > Peter Membrey > _______________________________________________ > 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. > _______________________________________________ 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.