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 _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts