In message <c542adee-19dd-4dab-a1bf-fb842c077...@rtty.us>, Bob Camp writes:
>The likely answer is that the trigger point must be changing. Yes that would be my first theory as well. > The question is whether it's changing because the >3336 is doing something (small waveform changes) or because the 5370 is >doing something. Yes, and obviously there are many experiments that can be performed to flesh out the details of that: Changing the 3336 output amplitude. Exchanging the signals, so the 3336 feeds ext-ref, and lab-standard feeds start+stop. Using a different lab-standard. Measuring opposite polarity etc. >I would make up / dig up a coax cable that is 8 degrees at 10 MHz. >Something around 1/2 meter long should do the job. As I said, I'm not really kitted out for RF work, so my selection of coax isn't that versatile and I don't have the crimp-tools or routine to make my own. >Next step would be some sort of filtering between the 3336 and the 5370. >That would help rule out harmonics and spurs from the generator as the >source of the problem. The 3336 delivers pretty clean output, so I expect a couple of sanity checks will exonerate it. Unfortunately my HP33120 does not have an external clock input, so I can't use that for the experiment. Anybody with a HP3325 or later HP33* with an external clock input can participate in this game... But to be honest, I'm not sure how much more work is really warranted for me, given that I don't think I can tune the 200MHz multipliers filters much better than they presently are. The really interesting experiments, in my mind, would be to ditch the 200MHz multiplier and feed 200MHz from a good generator with high purity instead. But then again: It is so much easier to just run the HP5370 on the internal clock and that solve^H^H^H^H^Hhides all the problems. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. _______________________________________________ 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.
