Thanks to all for the discussion, but I'm still not sure why I have a (now) consistent 1.495 hz frequency difference between the thunderbolt and the VE2ZAZ FLL.
On a similar note, forgive my ignorance, but is there a simple explanation why there are different frequency readings on my 5370B when selecting frequency with a 1s gate vs frequency with 100k samples? Not a few uHz, 1sec gate reading of the VE2ZAZ is 10,000,001.4946 Hz (+/- noise in the last digit) while 100k sample reading is 9,997,322.2 Hz +/- noise in the last four digits. Thanks, Bob the geology major On Tue, May 3, 2011 at 9:43 PM, Luis Cupido <cup...@mail.ua.pt> wrote: > Hi Bert, > > Well, without the averaging I think I was correct > (I was obviously not considering the averaging). > Your implementation with averaging surely smooth this proportionally > and yes you end up better than 0.0625 as more you integrate. > Please consider then the numbers you may find relevant and the > corresponding integration time. (that was not really the > point in my email). > > But since all topologies can average I presume you > agree that potential differences between systems > as remarked in my email still apply. Namely an offset > at a frequency drift that is basic behavior of any FLL > you wont have on a PLL. > > All that may fall below most practical needs(1), I agree... > But in the timenuts spirit ought to be pointed out... right ? ;-) > > Luis Cupido > ct1dmk. > > > p.s. (1) folks running several Cesium stds don't > be offended I'm not saying your needs are not practical :-) > ;-) hi.... > > > > > > > Bert, VE2ZAZ wrote: >> >> Luis, >> >> You said: <<Furthermore the frequency counting resolution is 16 seconds, >> so the ZAZ gpsdo won't lock better than 0.0625Hz.>> >> >> >> On my GPSDO design, a single 16-second frequency sample does have a >> resolution of 0.0625Hz. But the FLL firmware does averaging over as many >> samples as you want before adjusting the OCXO. So I don't agree with your >> statement that the ZAZ gpsdo won't lock better than 0.0625Hz. In fact, I >> have never seen my design go worse than 1x10E-9. It usually sit below >> 5x10E-10. This concurs with the many reports I got from other users. >> >> >> Please elaborate. >> >> Thanks, >> >> Bert, VE2ZAZ > > > _______________________________________________ > 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.
