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