Hi Ok, I got enough time to play a bit more with the 5370B today. Here's what I found (all running on the internal standard):
If I take the gate time out to 1 second, the frequency display reads as it should. If I look at the standard deviation on various samples of period I get some interesting data: With the instrument cold, I get some amazingly low (like 4 ps) standard deviations on 10K and 100K sample sets. With it cold I get 15-30 ps on 100 and 1K sample sets. Once things heat up I get numbers in the 20-30 ps for all sample sets. I'm guessing that means that nothing's major broke, but I still might find regulator that needs replacement. Bob On Mar 10, 2010, at 7:48 AM, Magnus Danielson wrote: > Bob Camp wrote: >> Hi >> Yes indeed, the period was measured with the two channels in the com mode >> and the reference >> into one of them. I hadn't considered the trigger offset issues and was >> expecting something >> sub-100 ps rather than 500 ps. Obviously I need to spend some "quality time" >> with this beast. >> Now I gotta figure out how to change the gate time :}...... > > If you do not fiddle with trigger levels, you _will_ loose accuracy. It is a > systematic error. > >> It sounds like my oscillator buffer board is going to get butchered pretty >> soon. > > I hope you mean modified. Applying a short at the right point improves the > situation, but you don't need that to get started. It is a refinement that > could wait for a little while. > > Cheers, > Magnus > > _______________________________________________ > 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.