I am using the 1 PPS for the trigger. Pete. On 11/3/2016 8:59 AM, Antonio A. S. Magalhaes wrote: > > Pete, > > Tell us about your trigger: where is it? > > Regards, > > Antonio/CT1TE > > --- > > A 2016-11-03 12:20, Peter Reilley escreveu: > >> I am the proverbial man with too many clocks and I don't know what >> time it is. >> To correct this situation I have decided to calibrate everything. >> >> I have a HP 5370B, a HP 6370A, and a HP 5328A all with the TCXO >> option. I also >> have some TCXO modules. I figured that I would calibrate them >> against my Trimble >> Resolution T GPS receiver. >> >> I put the 1 PPS signal in one channel of my scope and one of the 10 MHz TCXO >> signals in the other channel and look at the phase relationship. The >> TCXO's are >> already close enough that I should not be out by more than a fraction >> of a waveform. >> I understand that I have to deal with the 1 PPS without sawtooth correction. >> >> I expected to see the 10 MHz signal bounce around but not move more than 1/2 >> of a wave length. Instead I see the 10 MHz waveform appear steady >> for a few seconds >> then jump a significant portion of the wave. The jump is too much >> to be confident >> that I have not slipped one cycle. >> >> Can I do what I am trying to do or am I missing something? >> >> Pete. >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com <mailto:time-nuts@febo.com> >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there.

Well, which 1PPS is the trigger? Is it from a "bare GPS"? Even the GPS timing units will have the (un-sawtooth-corrected) PPS phase make jumps by 20ns to 40ns peak-to-peak and that's a significant portion of the 100ns period of your 10MHz. Typical unsawtooth-corrected PPS phase jumps: http://www.leapsecond.com/pages/m12/sawtooth.htm Tim N3QE On Thu, Nov 3, 2016 at 9:22 AM, Peter Reilley <preilley_454@comcast.net> wrote: > I am using the 1 PPS for the trigger. > > Pete. > > > On 11/3/2016 8:59 AM, Antonio A. S. Magalhaes wrote: > >> >> Pete, >> >> Tell us about your trigger: where is it? >> >> Regards, >> >> Antonio/CT1TE >> >> --- >> >> A 2016-11-03 12:20, Peter Reilley escreveu: >> >> I am the proverbial man with too many clocks and I don't know what time >>> it is. >>> To correct this situation I have decided to calibrate everything. >>> >>> I have a HP 5370B, a HP 6370A, and a HP 5328A all with the TCXO option. >>> I also >>> have some TCXO modules. I figured that I would calibrate them against >>> my Trimble >>> Resolution T GPS receiver. >>> >>> I put the 1 PPS signal in one channel of my scope and one of the 10 MHz >>> TCXO >>> signals in the other channel and look at the phase relationship. The >>> TCXO's are >>> already close enough that I should not be out by more than a fraction of >>> a waveform. >>> I understand that I have to deal with the 1 PPS without sawtooth >>> correction. >>> >>> I expected to see the 10 MHz signal bounce around but not move more than >>> 1/2 >>> of a wave length. Instead I see the 10 MHz waveform appear steady for >>> a few seconds >>> then jump a significant portion of the wave. The jump is too much to >>> be confident >>> that I have not slipped one cycle. >>> >>> Can I do what I am trying to do or am I missing something? >>> >>> Pete. >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts@febo.com <mailto:time-nuts@febo.com> >>> To unsubscribe, go to https://www.febo.com/cgi-bin/m >>> ailman/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/m > ailman/listinfo/time-nuts > and follow the instructions there. >

Hi If your TCXO is off by 1 ppm, it will slip 10 cycles per second at 10 MHz. If it is off by 0.1 ppm it will slip a full cycle at 10 MHz. If it is off by 0.01 ppm *and* uses some sort of digital compensation, it will hop around. If the GPS is not sawtooth corrected it will hop by a good fraction of a cycle at 10 MHz If the GPS is not surveyed in and seeing many satellites, it may hop by more than a cycle at 10 MHz. Best bet: Divide the TCXO down to a much lower frequency (< 100 Hz). Use the 5370 to look at the delta between the GPS pulse and the TCXO output. Bob > On Nov 3, 2016, at 9:22 AM, Peter Reilley <preilley_454@comcast.net> wrote: > > I am using the 1 PPS for the trigger. > > Pete. > > > On 11/3/2016 8:59 AM, Antonio A. S. Magalhaes wrote: >> >> Pete, >> >> Tell us about your trigger: where is it? >> >> Regards, >> >> Antonio/CT1TE >> >> --- >> >> A 2016-11-03 12:20, Peter Reilley escreveu: >> >>> I am the proverbial man with too many clocks and I don't know what time it is. >>> To correct this situation I have decided to calibrate everything. >>> >>> I have a HP 5370B, a HP 6370A, and a HP 5328A all with the TCXO option. I also >>> have some TCXO modules. I figured that I would calibrate them against my Trimble >>> Resolution T GPS receiver. >>> >>> I put the 1 PPS signal in one channel of my scope and one of the 10 MHz TCXO >>> signals in the other channel and look at the phase relationship. The TCXO's are >>> already close enough that I should not be out by more than a fraction of a waveform. >>> I understand that I have to deal with the 1 PPS without sawtooth correction. >>> >>> I expected to see the 10 MHz signal bounce around but not move more than 1/2 >>> of a wave length. Instead I see the 10 MHz waveform appear steady for a few seconds >>> then jump a significant portion of the wave. The jump is too much to be confident >>> that I have not slipped one cycle. >>> >>> Can I do what I am trying to do or am I missing something? >>> >>> Pete. >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts@febo.com <mailto: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.

Bob has stated this, but perhaps not emphasized that, when you sample the phase of a 10 MHz clock once a second, you are essentially folding the 20 millionth nyquist band down to baseband. So you can alias any integer multiple of 1 Hz as if it were 10 MHz, i.e. 10 MHz + 1Hz will hold phase to 1 Hz (sampled once a second) just as well as 10 MHz would. On Thu, Nov 3, 2016 at 1:00 PM, Bob Camp <kb8tq@n1k.org> wrote: > Hi > > If your TCXO is off by 1 ppm, it will slip 10 cycles per second at 10 MHz. > If it is off by 0.1 ppm it will slip a full cycle at 10 MHz. > If it is off by 0.01 ppm *and* uses some sort of digital compensation, it > will hop around. > If the GPS is not sawtooth corrected it will hop by a good fraction of a > cycle at 10 MHz > If the GPS is not surveyed in and seeing many satellites, it may hop by > more than a cycle at 10 MHz. > > Best bet: > > Divide the TCXO down to a much lower frequency (< 100 Hz). Use the 5370 to > look at the > delta between the GPS pulse and the TCXO output. > > Bob > > > > On Nov 3, 2016, at 9:22 AM, Peter Reilley <preilley_454@comcast.net> > wrote: > > > > I am using the 1 PPS for the trigger. > > > > Pete. > > > > > > On 11/3/2016 8:59 AM, Antonio A. S. Magalhaes wrote: > >> > >> Pete, > >> > >> Tell us about your trigger: where is it? > >> > >> Regards, > >> > >> Antonio/CT1TE > >> > >> --- > >> > >> A 2016-11-03 12:20, Peter Reilley escreveu: > >> > >>> I am the proverbial man with too many clocks and I don't know what > time it is. > >>> To correct this situation I have decided to calibrate everything. > >>> > >>> I have a HP 5370B, a HP 6370A, and a HP 5328A all with the TCXO > option. I also > >>> have some TCXO modules. I figured that I would calibrate them > against my Trimble > >>> Resolution T GPS receiver. > >>> > >>> I put the 1 PPS signal in one channel of my scope and one of the 10 > MHz TCXO > >>> signals in the other channel and look at the phase relationship. The > TCXO's are > >>> already close enough that I should not be out by more than a fraction > of a waveform. > >>> I understand that I have to deal with the 1 PPS without sawtooth > correction. > >>> > >>> I expected to see the 10 MHz signal bounce around but not move more > than 1/2 > >>> of a wave length. Instead I see the 10 MHz waveform appear steady > for a few seconds > >>> then jump a significant portion of the wave. The jump is too much to > be confident > >>> that I have not slipped one cycle. > >>> > >>> Can I do what I am trying to do or am I missing something? > >>> > >>> Pete. > >>> > >>> _______________________________________________ > >>> time-nuts mailing list -- time-nuts@febo.com <mailto: > 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. > > _______________________________________________ > 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. >