Hi As normally used, the term “aging” means the long term drift in the frequency of an OCXO. It is independent of the temperature effects and things like retrace, warmup, and voltage stability. It is rare that there is any impact on the aging of a properly designed OCXO from drift of the oven temperature.
Any time you try to estimate (or measure) aging on an OCXO, you will have a hard time separating it from the other things that affect the frequency of the oscillator. The somewhat amazing holdover estimates on the HP units are one example of this problem. It does not take much testing to quickly realize that they are far more often wrong than right on a unit that has been on power for less than a few weeks. Bob > On Oct 6, 2016, at 1:11 PM, Chris Albertson <[email protected]> wrote: > > Wouldn't "aging" be the change in the temperature v. frequncy graph over > time? It is hard to hold temperture constant so maybe record the > function at several different times. > > This is one big advantage of using a microprocessor inside the GPSDO, It > can log internal data to either a SD card or use a USB link to a PC to be > recored in log files. Even my "simple as possible" GPSDO push data to a > PC over USB. It is easy to glue a temperature sensor to "whatever" and > log it > > On Wed, Oct 5, 2016 at 10:14 PM, Hal Murray <[email protected]> wrote: > >> >> [email protected] said: >>> Unless the oscillator is still warming up, 5 minutes or even 60 is way >> too >>> short a time to look at aging. For aging, you will want to look at the >>> change in DAC values over several days at least. >> >> I think it's worse than that. You have to hold the temperature constant, >> and >> maybe even the power supply voltage. A probe on the crystal can might >> allow >> you to correct for temperature. >> >> >> >> >> -- >> These are my opinions. I hate spam. >> >> >> >> _______________________________________________ >> 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. >> > > > > -- > > Chris Albertson > Redondo Beach, California > _______________________________________________ > 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.
