(Interesting timing given the SR620 discussion.) I'm (finally) getting my GPIB gizmo working.
I have a HP 5334B running off its (good) internal osc looking at the output of a Z3801A. Assuming the Z3801A is stable, this is a backwards way of looking at the internal osc. (There is a shared in/out connector for the internal clock, so I can't see the internal osc if I feed it an ext reference.) I left it running for a night with the mostly default setup and 100 cycle averaging. I think the default gate time is 0.3 seconds. Answers ranged from: F +9.999999330E+06 F +9.999999333E+06 I've had this setup running for several weeks. The bottom digit doesn't fit on the display, so I never noticed there was anything interesting going on down there. The 100 cycle averaging has a button on the front panel. Without it, the display is one digit shorter. Yesterday, I got it running with a single 60 second gate. Now it's wobbling between: F +9.999999339E+06 F +9.999999340E+06 I was a bit surprised there is such a difference. Is this all obvious to anybody who has carefully read the manual? Of course, now that I think about it, averaging frequency measurements seems less helpful that simply using a longer measurement time. But I'm still surprised the answers were so different. Another quirk I noticed. They truncate rather than round for the display on the front panel. 9.999999339 shows up as 9.99999933 rather than 9.99999934 Is there anything else like this I should watch out for? Does anybody have a quick summary on how to get good results or traps to avoid? -- These are my opinions, not necessarily my employer's. I hate spam. _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts