Skip, I had some fun post-processing your data.
If we believe this to be a representative set, then on average they age about -3E-11/year. Plotting it (error vs. years and error/year vs. years) gives no real clue.
Cheers, Magnus On 08/28/2015 04:37 AM, Skip Withrow 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.
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