Here are my $0.02... Magnus Danielson wrote: > From: Dr Bruce Griffiths <bruce.griffiths@xtra.co.nz> > Subject: Re: [time-nuts] How to measure Allan Deviation? > Date: Tue, 24 Oct 2006 10:52:21 +1300 > Message-ID: <453D3995.8080004@xtra.co.nz> > > >> Tom >> > > Hi Bruce, > > >> In comparing 2 oscillators do you mean >> >> 1) Connecting one oscillator to the FREQ STD input at the rear of the >> 5370A, selecting the external timebase and connecting the other >> oscillator to the Front panel FREQ/PERIOD input and then selecting >> frequency measurement which in effect gives the frequency ratio of the 2 >> oscillators? >> > > I have advocated this approach, but nobody seemed to care. > > HP says in the 5316B manual (probably in other manuals, but that's where I saw it first), that it is best to compare 2 oscillators by plugging them in START and STOP respectively, but NOT to use one as a standard, because averaging works better (or simply, works) when the internal standard is async with either START or STOP signals. > Cheers, > Magnus > Didier

Didier Juges wrote: > Here are my $0.02... > > Magnus Danielson wrote: > >> From: Dr Bruce Griffiths <bruce.griffiths@xtra.co.nz> >> Subject: Re: [time-nuts] How to measure Allan Deviation? >> Date: Tue, 24 Oct 2006 10:52:21 +1300 >> Message-ID: <453D3995.8080004@xtra.co.nz> >> >> >> >>> Tom >>> >>> >> Hi Bruce, >> >> >> >>> In comparing 2 oscillators do you mean >>> >>> 1) Connecting one oscillator to the FREQ STD input at the rear of the >>> 5370A, selecting the external timebase and connecting the other >>> oscillator to the Front panel FREQ/PERIOD input and then selecting >>> frequency measurement which in effect gives the frequency ratio of the 2 >>> oscillators? >>> >>> >> I have advocated this approach, but nobody seemed to care. >> >> >> > HP says in the 5316B manual (probably in other manuals, but that's where > I saw it first), that it is best to compare 2 oscillators by plugging > them in START and STOP respectively, but NOT to use one as a standard, > because averaging works better (or simply, works) when the internal > standard is async with either START or STOP signals. > >> Cheers, >> Magnus >> >> > > Didier > _______________________________________________ > time-nuts mailing list > time-nuts@febo.com > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > This may also be helpful in mitigating the effect of some of the differential linearity errors of the HP5370A Bruce

Dr Bruce Griffiths wrote: > Didier > > You may also find this useful > > http://www.wenzel.com/documents/waveform.html > > There are some other items that may be of interest at: > > http://www.wenzel.com/documents/library.html > > Though you may not want to build the water barometer!! > > Bruce > Both links are great, thank you. Particularly, the 2nd one links to a program to isolate the noise of 3 oscillators from 3 pairs of comparisons. That's what I was looking for. Too bad the source code is not provided, but if the program works, that'll be fine. Thanks again Didier

Dr Bruce Griffiths wrote: > Didier > > Did you get my comment on HP5370A differential linearity errors. > It made it to the list but I didn't receive a bounced copy. > > Bruce > > > _______________________________________________ > time-nuts mailing list > time-nuts@febo.com > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > Yes I have. However, I have not completely digested the implications, I have a mild to severe case of information overload at the moment (like drinking from a fire hose...), but it's a good thing though! Didier

Didier Juges wrote: > I do not understand the signal on the rear trigger outputs. At the > moment, I have a single 10 MHz sine signal fed to the START channel, and > the 5370 is set to TI, MEAN, SAMPLE SIZE 1, + TI ONLY, START channel > triggers on rise and STOP channel triggers on fall, and START COM is > selected. The instrument displays about 60 nS (fairly stable, 150 ps > jitter) or so at the moment. The rear START trigger shows a negative > going pulse (400uS wide, at 62 mS rep rate), with the rising edge > (positive going) synchronous with the 10 MHz signal and the phase is > adjustable using the *STOP* trigger level! When I trigger the scope on > the falling edge of the START trigger output, the 10 MHz signal seems to > drift, and the trigger setting has no effect, except that if adjusted > too far, the instrument stops updating the display. > > Apparently, the START trigger adjustment has no effect on the timing of > the rear START trigger output, but will cause the display to freeze if > the START trigger is set to either extreme, even though the START > trigger output on the rear does not change. > > The STOP trigger output works the opposite: it responds to the START > trigger level. Could it be that the outputs are reversed on my instrument? > > I am not sure this is a complete description, and maybe there is an > obvious answer that I am missing, but I am perplexed. > > Didier The 5370A processor can swap the front panel START and STOP inputs over via an ECL multiplexer on bord A22. The rear panel outputs reflect the actual selected START and STOP events not necessarily the signals connected to the front panel START and STOP connectors. Bruce

Didier START and STOP selection is even more complex than I indicated. START SOURCE STOP SOURCE REAR PANEL START TRIGGER REAR PANEL STOP TRIGGER Front panel START Front Panel STOP Front Panel START Front Panel STOP Front panel STOP Front Panel STOP Front Panel STOP Front Panel STOP Front panel START Front Panel START Front Panel START Front Panel START Front panel STOP Front Panel START Front Panel STOP Front Panel START If you have a manual for the 5370A this is all documented in the programming section (except for the connection of the rear panel START and STOP trigger outputs which can be gleaned by perusing the circuit diagram for A22.. Bruce

Dr Bruce Griffiths wrote: > Didier Juges wrote: > >> I do not understand the signal on the rear trigger outputs. At the >> moment, I have a single 10 MHz sine signal fed to the START channel, and >> the 5370 is set to TI, MEAN, SAMPLE SIZE 1, + TI ONLY, START channel >> triggers on rise and STOP channel triggers on fall, and START COM is >> selected. The instrument displays about 60 nS (fairly stable, 150 ps >> jitter) or so at the moment. The rear START trigger shows a negative >> going pulse (400uS wide, at 62 mS rep rate), with the rising edge >> (positive going) synchronous with the 10 MHz signal and the phase is >> adjustable using the *STOP* trigger level! When I trigger the scope on >> the falling edge of the START trigger output, the 10 MHz signal seems to >> drift, and the trigger setting has no effect, except that if adjusted >> too far, the instrument stops updating the display. >> >> Apparently, the START trigger adjustment has no effect on the timing of >> the rear START trigger output, but will cause the display to freeze if >> the START trigger is set to either extreme, even though the START >> trigger output on the rear does not change. >> >> The STOP trigger output works the opposite: it responds to the START >> trigger level. Could it be that the outputs are reversed on my instrument? >> >> I am not sure this is a complete description, and maybe there is an >> obvious answer that I am missing, but I am perplexed. >> >> >> > Didier > > The 5370A processor can swap the front panel START and STOP inputs over > via an ECL multiplexer on bord A22. > The rear panel outputs reflect the actual selected START and STOP events > not necessarily the signals connected to the front panel START and STOP > connectors. > > Bruce > Good catch, but I thought that only came to play when +/-TI was selected, and I have selected +TI ONLY? Didier

Didier Juges wrote: > Dr Bruce Griffiths wrote: > >> Didier Juges wrote: >> >> >>> I do not understand the signal on the rear trigger outputs. At the >>> moment, I have a single 10 MHz sine signal fed to the START channel, and >>> the 5370 is set to TI, MEAN, SAMPLE SIZE 1, + TI ONLY, START channel >>> triggers on rise and STOP channel triggers on fall, and START COM is >>> selected. The instrument displays about 60 nS (fairly stable, 150 ps >>> jitter) or so at the moment. The rear START trigger shows a negative >>> going pulse (400uS wide, at 62 mS rep rate), with the rising edge >>> (positive going) synchronous with the 10 MHz signal and the phase is >>> adjustable using the *STOP* trigger level! When I trigger the scope on >>> the falling edge of the START trigger output, the 10 MHz signal seems to >>> drift, and the trigger setting has no effect, except that if adjusted >>> too far, the instrument stops updating the display. >>> >>> Apparently, the START trigger adjustment has no effect on the timing of >>> the rear START trigger output, but will cause the display to freeze if >>> the START trigger is set to either extreme, even though the START >>> trigger output on the rear does not change. >>> >>> The STOP trigger output works the opposite: it responds to the START >>> trigger level. Could it be that the outputs are reversed on my instrument? >>> >>> I am not sure this is a complete description, and maybe there is an >>> obvious answer that I am missing, but I am perplexed. >>> >>> >>> >>> >> Didier >> >> The 5370A processor can swap the front panel START and STOP inputs over >> via an ECL multiplexer on bord A22. >> The rear panel outputs reflect the actual selected START and STOP events >> not necessarily the signals connected to the front panel START and STOP >> connectors. >> >> Bruce >> >> > Good catch, but I thought that only came to play when +/-TI was > selected, and I have selected +TI ONLY? > > Didier > > _______________________________________________ > time-nuts mailing list > time-nuts@febo.com > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > Didier That's not the way I interpret the manual or the article on the 5370 in the HP journal. +TI ignores all STOP inputs until after the START event. +-TI START before STOP is a positive time interval STOP before START is a negative time interval. Internal logic implements a precedence detctor so that the relative order of accepted start and stop events can be determined. Bruce

Hi Bruce, Dr Bruce Griffiths wrote: > Didier Juges wrote: > >> Dr Bruce Griffiths wrote: >> >> >>> Didier Juges wrote: >>> >>> >>> >>>> I do not understand the signal on the rear trigger outputs. At the >>>> moment, I have a single 10 MHz sine signal fed to the START channel, and >>>> the 5370 is set to TI, MEAN, SAMPLE SIZE 1, + TI ONLY, START channel >>>> triggers on rise and STOP channel triggers on fall, and START COM is >>>> selected. The instrument displays about 60 nS (fairly stable, 150 ps >>>> jitter) or so at the moment. The rear START trigger shows a negative >>>> going pulse (400uS wide, at 62 mS rep rate), with the rising edge >>>> (positive going) synchronous with the 10 MHz signal and the phase is >>>> adjustable using the *STOP* trigger level! When I trigger the scope on >>>> the falling edge of the START trigger output, the 10 MHz signal seems to >>>> drift, and the trigger setting has no effect, except that if adjusted >>>> too far, the instrument stops updating the display. >>>> >>>> Apparently, the START trigger adjustment has no effect on the timing of >>>> the rear START trigger output, but will cause the display to freeze if >>>> the START trigger is set to either extreme, even though the START >>>> trigger output on the rear does not change. >>>> >>>> The STOP trigger output works the opposite: it responds to the START >>>> trigger level. Could it be that the outputs are reversed on my instrument? >>>> >>>> I am not sure this is a complete description, and maybe there is an >>>> obvious answer that I am missing, but I am perplexed. >>>> >>>> >>>> >>>> >>>> >>> Didier >>> >>> The 5370A processor can swap the front panel START and STOP inputs over >>> via an ECL multiplexer on bord A22. >>> The rear panel outputs reflect the actual selected START and STOP events >>> not necessarily the signals connected to the front panel START and STOP >>> connectors. >>> >>> Bruce >>> >>> >>> >> Good catch, but I thought that only came to play when +/-TI was >> selected, and I have selected +TI ONLY? >> >> Didier >> >> _______________________________________________ >> time-nuts mailing list >> time-nuts@febo.com >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> >> >> > Didier > > That's not the way I interpret the manual or the article on the 5370 in > the HP journal. > > +TI ignores all STOP inputs until after the START event. > +-TI START before STOP is a positive time interval STOP before START is > a negative time interval. Internal logic implements a precedence detctor > so that the relative order of accepted start and stop events can be > determined. > > Bruce > > You are correct of course, I *assumed* the counter would automatically swap the START and STOP rear trigger outputs as needed when the +/-TI mode was selected, but that in +TI ONLY mode, there should be no need to swap START and STOP, therefore the rear trig outputs would be fixed. I have a lot more reading to do, it's a big manual. I have a pdf of it on my web site and I printed all this week end, big job! Can you send me the pdf of the HP journal about the 5370? If it's too big to attach, can you upload it to my web site? dns: ftp.ko4bb.com login: manuals password: manuals Thanks Didier

Didier Juges wrote: > Hi Bruce, > > Dr Bruce Griffiths wrote: > >> Didier Juges wrote: >> >> >>> Dr Bruce Griffiths wrote: >>> >>> >>> >>>> Didier Juges wrote: >>>> >>>> >>>> >>>> >>>>> I do not understand the signal on the rear trigger outputs. At the >>>>> moment, I have a single 10 MHz sine signal fed to the START channel, and >>>>> the 5370 is set to TI, MEAN, SAMPLE SIZE 1, + TI ONLY, START channel >>>>> triggers on rise and STOP channel triggers on fall, and START COM is >>>>> selected. The instrument displays about 60 nS (fairly stable, 150 ps >>>>> jitter) or so at the moment. The rear START trigger shows a negative >>>>> going pulse (400uS wide, at 62 mS rep rate), with the rising edge >>>>> (positive going) synchronous with the 10 MHz signal and the phase is >>>>> adjustable using the *STOP* trigger level! When I trigger the scope on >>>>> the falling edge of the START trigger output, the 10 MHz signal seems to >>>>> drift, and the trigger setting has no effect, except that if adjusted >>>>> too far, the instrument stops updating the display. >>>>> >>>>> Apparently, the START trigger adjustment has no effect on the timing of >>>>> the rear START trigger output, but will cause the display to freeze if >>>>> the START trigger is set to either extreme, even though the START >>>>> trigger output on the rear does not change. >>>>> >>>>> The STOP trigger output works the opposite: it responds to the START >>>>> trigger level. Could it be that the outputs are reversed on my instrument? >>>>> >>>>> I am not sure this is a complete description, and maybe there is an >>>>> obvious answer that I am missing, but I am perplexed. >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>> Didier >>>> >>>> The 5370A processor can swap the front panel START and STOP inputs over >>>> via an ECL multiplexer on bord A22. >>>> The rear panel outputs reflect the actual selected START and STOP events >>>> not necessarily the signals connected to the front panel START and STOP >>>> connectors. >>>> >>>> Bruce >>>> >>>> >>>> >>>> >>> Good catch, but I thought that only came to play when +/-TI was >>> selected, and I have selected +TI ONLY? >>> >>> Didier >>> >>> _______________________________________________ >>> time-nuts mailing list >>> time-nuts@febo.com >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> >>> >>> >>> >> Didier >> >> That's not the way I interpret the manual or the article on the 5370 in >> the HP journal. >> >> +TI ignores all STOP inputs until after the START event. >> +-TI START before STOP is a positive time interval STOP before START is >> a negative time interval. Internal logic implements a precedence detctor >> so that the relative order of accepted start and stop events can be >> determined. >> >> Bruce >> >> >> > You are correct of course, I *assumed* the counter would automatically > swap the START and STOP rear trigger outputs as needed when the +/-TI > mode was selected, but that in +TI ONLY mode, there should be no need to > swap START and STOP, therefore the rear trig outputs would be fixed. > > I have a lot more reading to do, it's a big manual. I have a pdf of it > on my web site and I printed all this week end, big job! > > Can you send me the pdf of the HP journal about the 5370? > If it's too big to attach, can you upload it to my web site? > dns: ftp.ko4bb.com > login: manuals > password: manuals > > Thanks > > Didier > > > _______________________________________________ > time-nuts mailing list > time-nuts@febo.com > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > Didier Will do as soon as I find the particular issue again. May take a little while as I haven't looked at it for a year or so. Bruce