> Tom's plots at http://www.leapsecond.com/pages/z3801a-osc/ show 13 > Z3801As running in unlocked mode, measured against one of his most > excellent references. So I think that plot shows what you're looking > for. I was just trying to show what you get when you are running in the > normal locked condition (my units almost never go into holdover, so I > was more interested in what the normal behavior was). > > One thing that's not clear from Tom's page, though, is whether the units > were in "smart" holdover mode (ie, no GPS signal but the CPU still > steering based on its learned aging curve) or truly freestanding with no > EFC being applied.
John, I'm pretty sure those Z3801A were in factory reset mode when I made the stability measurements. For that experiment I was only interested in short-term stability; a range of tau where the smart ageing correction has little or no effect. You also asked about z3801a free-run vs. GPS locked plots. I found old data for GPSDO #4 (of the 13 I tested in 2002). Free-run stability for #4. http://www.leapsecond.com/pages/z3801a-osc/log8007v.gif GPS locked stability for #4: http://www.leapsecond.com/museum/z3801a/log8286v.gif Here I put the two runs in color on the same plot: http://www.leapsecond.com/museum/z3801a/z3801a-free-lock.gif Between the three plots you get a good feel for the function of a GPSDO. /tvb _______________________________________________ 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.