Hi
> On Sep 22, 2015, at 11:49 PM, Bob Benward <[email protected]> wrote: > > Continuing this discussion, I have included a PDF showing the past 30days of > EFC. Amazingly, the drift has reversed direction! Yes, it’s fairly common. The standard advice with OCXO’s is to leave them on power as much as you possibly can. A bit more detailed explanation: You have multiple processes that contribute to aging. They each have different rates, and directions. Most of them follow a exponential decay. On a crummy oscillator, you may have one really terrible process that dominates everything. On a good part, you will see reversals and multiple slopes. Bob > Anyone have any insights > into this behavior? Each data point represents 10 seconds. > > Bob > >>>> -----Original Message----- >>>> From: time-nuts [mailto:[email protected]] On Behalf Of Magnus >>>> Danielson >>>> Sent: Tuesday, September 22, 2015 5:46 PM >>>> To: [email protected] >>>> Cc: [email protected] >>>> Subject: Re: [time-nuts] Z380XA The saga of the aging 10811 >>>> >>>> Analog is nice and dandy, but for longer time-constants, digital does > have it's >>>> merits. >>>> >>>> Wonder how good resolution one really need for sensing and how to > achieve >>>> it. >>>> >>>> Cheers, >>>> Magnus >>>> >>>> >>>> On 09/15/2015 12:58 PM, Bob Camp wrote: >>>>> Hi >>>>> >>>>> To the extent that the oven controller is an integrator, it only >>>>> integrates over a couple of seconds. >>>>> >>>>> Bob >>>>> >>>>>> On Sep 14, 2015, at 5:58 PM, Bob Benward <[email protected]> >>>> wrote: >>>>>> >>>>>> Robert, >>>>>> The drift has slowed down to something around 8xE-10, which is a bit >>>>>> over the spec of <5E-10. But this is the single oven, I have not >>>>>> reassembled the double oven yet. >>>>>> >>>>>> If the oven regulation was off, I would suspect I would see the EFC >>>>>> go back and forth a bit, maybe a general trend up, but some retracing >>>>>> would be expected. The oven control is an integrator, so unless the >>>>>> offset is very large compare to the output of the thermistor, a >>>>>> continuously changing offset voltage will not have a large effect on >>>>>> setpoint. A crystal resonator will drift about 1-5E-8/degC, so I >>>>>> guess a loose temperature control would certainly exhibit the drift I > am >>>> seeing. >>>>>> >>>>>> Bob >>>>>> >>>>>> >>>>>> >>>>>>>>> -----Original Message----- >>>>>>>>> From: time-nuts [mailto:[email protected]] On Behalf Of >>>>>>>>> George Atkinson >>>>>>>>> Sent: Monday, September 14, 2015 2:42 PM >>>>>>>>> To: Discussion of precise time and frequency measurement >>>>>>>>> Subject: Re: [time-nuts] Z380XA The saga of the aging 10811 >>>>>>>>> >>>>>>>>> Well, if the batch/revision of op-amps had a doping, contamination >>>>>>>>> or >>>>>> similar >>>>>>>>> issue, the input offset could be drifting fairly constantly >>>>>>>>> causing a temperature channge in one direction. >>>>>>>>> >>>>>>>>> Robert G8RPI. >>>>>>>>> >>>>>>>>> On 9 September 2015 at 04:40, Bob Benward >>>> <[email protected]> >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>>> Hi Ed, >>>>>>>>>> OK, a bad oven. I can buy that. But then if the oscillator is >>>>>>>>>> constantly drifting, would that not imply that the oven is >>>>>>>>>> constantly changing temperature, in one direction? >>>>>>>>>> >>>>>>>>>> BTW, the curve is starting to flatten out. It might be flat >>>>>>>>>> before It gets to 1000K counts. >>>>>>>>>> >>>>>>>>>> Bob >>>>>>>>>> >>>>>>>>>>>>> -----Original Message----- >>>>>>>>>>>>> From: time-nuts [mailto:[email protected]] On Behalf >>>>>>>>>>>>> Of ed breya >>>>>>>>>>>>> Sent: Tuesday, September 08, 2015 10:55 AM >>>>>>>>>>>>> To: [email protected] >>>>>>>>>>>>> Subject: Re: [time-nuts] Z380XA The saga of the aging 10811 >>>>>>>>>>>>> >>>>>>>>>>>>> It could be that the inner oven temperature regulation is off >>>>>>>>>>>>> a bit, or >>>>>>>>>> even >>>>>>>>>>>>> failed. There was a report at one of the popular time-nuts >>>>>>>>>>>>> oriented >>>>>>>>>> websites (I >>>>>>>>>>>>> forget which one, but it's the one that had extensive coverage >>>>>>>>>>>>> of the >>>>>>>>>> Z3801A) >>>>>>>>>>>>> about inner oven problems a few years ago. I took mine apart >>>>>>>>>>>>> and found >>>>>>>>>> that >>>>>>>>>>>>> it had an IC of a particular date code range that was prone to >>>>>> failure. >>>>>>>>>> I can't >>>>>>>>>>>>> recall whether I replaced it with the same type but different >>>>>>>>>>>>> date, or >>>>>>>>>> an >>>>>>>>>>>>> alternative, but it worked just fine after that, with no >>>>>>>>>>>>> tweaking of >>>>>>>>>> coarse EFC >>>>>>>>>>>>> needed. >>>>>>>>>>>>> >>>>>>>>>>>>> The IC was a dual opamp I think, that controlled the oven >>>>>>>>>>>>> temperature according to the thermistor signal, and drove the >>>>>> heater >>>>>>>>> transistor(s). >>>>>>>>>>>>> It was a fairly high performance type, but not that unusual. I >>>>>>>>>>>>> think it >>>>>>>>>> was a >>>>>>>>>>>>> Linear Technology brand part. >>>>>>>>>>>>> >>>>>>>>>>>>> Ed >>>>>>>>>>>>> _______________________________________________ >>>>>>>>>>>>> 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. >>>>>>>>>>>>> ----- >>>>>>>>>>>>> No virus found in this message. >>>>>>>>>>>>> Checked by AVG - www.avg.com >>>>>>>>>>>>> Version: 2015.0.6140 / Virus Database: 4409/10580 - Release >>>> Date: >>>>>>>>>>>>> 09/05/15 >>>>>>>>>> >>>>>>>>>> _______________________________________________ >>>>>>>>>> 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. >>>>>>>>> ----- >>>>>>>>> No virus found in this message. >>>>>>>>> Checked by AVG - www.avg.com >>>>>>>>> Version: 2015.0.6140 / Virus Database: 4419/10639 - Release Date: >>>>>>>>> 09/14/15 >>>>>> >>>>>> _______________________________________________ >>>>>> 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. >>>>> >>>> _______________________________________________ >>>> 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. >>>> ----- >>>> No virus found in this message. >>>> Checked by AVG - www.avg.com >>>> Version: 2015.0.6140 / Virus Database: 4419/10665 - Release Date: >>>> 09/19/15 > <Z3805A EFC 30days.pdf>_______________________________________________ > 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.
