Hi Based on looking at about 40 or so similar units - I have never seen one that was > 1x10^-9 off frequency. Finding one that is >5x10^-10 off after running for a > few days is rare in my experience. The makes and models ranged over several types and companies. I have seen no group that is any better or worse than the rest. All of the parts I have seen apparently left the factory at one setting and never got adjusted in the field. Many of the date codes on mine go back into the 2000 ~ 2003 era.
With no way to track running hours, there is not a lot you can do with this data in terms of “power on aging”. I think it’s fair to say that in whatever environment they were in, you didn’t see anything even remotely close to the sort of 1x10^-9 per year you see quoted as aging numbers on these gizmos. Bob > On Aug 27, 2015, at 10:37 PM, Skip Withrow <[email protected]> wrote: > > Hello time-nuts, > > As an experiment I took 10 FEI FE-5650A rubidium oscillators and measured > their frequency error (units were chosen randomly). These were 15MHz units > taken directly off the telecom cards with no modifications. These units > never went to China, and are pulls from working systems. Each unit was > allowed to warmup for a couple of hours before the measurement was made. > > Results were: > Unit # Date Code Error > 301302 0716 -2.87 x 10E-10 > C312570 0839 +4.16 x 10E-11 > 79119 0701 -1.01 x 10E-10 > C312324 0812 -2.54 x 10E-10 > 69008 0450 -2.52 x 10E-10 > 60495 0352 -6.05 x 10E-10 > 78894 0651 -4.30 x 10E-11 > 79287 0701 -2.77 x 10E-10 > 71379 0523 -1.80 x 10E-10 > 78871 0651 -8.58 x 10E-10 > > Date code is YYWW. The units with a 'C' in front are after production was > moved to China. > > All but 1 of the units ran slow (my reference was a Trimble GPSTM, locked > to GPS, so should be within a couple parts in 10E-12). I doubt that FEI's > reference was off by a couple parts in 10E-10, so my conclusion is that > they tend to age slower while in service (they are disciplined to GPS in > the application anyway). > > These oscillators can be stepped by 6.8 x 10E-13 via digital control. When > modified by us at RDR we set them +/-2x10E-11 (for a 00 00 00 00 control > word). It would be interesting to know how many hours are on each of the > test units, but I know of no way to obtain that information (unless it is > part of the secret information that be read out of the unit). > > Regards, > Skip Withrow > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
