[time-nuts] Thermal impact on OCXO
holrum at hotmail.com
Fri Nov 18 22:34:07 EST 2016
Several years ago I replaced the OCXOs in some Tektronix DC5010 counters with surplus Oscilloquartz 8663 DOCXOs. The darn things have freaky good aging characteristics. They have been on 24/7 (except for a few brief power-outages) for over 3 years. After a month I set their freq against a cesium oscillator. They still show 10 MHz out to 8 or 9 decimal places.
I just got in an Oscilloquartz Star-4 ATDC (automatic temperature / drift compensation) that uses the same DOCXO. They take 24 hours from a cold start before the ATDC learning kicks in (you can fake it out by power cycling during that interval and it thinks it was a brief outage and reports a 1 hour learning delay). After an unspecified time (at least several days) the device learns the compensation characteristics and the holdover performance status switches from POOR to IN-SPEC. I have not yet gotten it past the learning stage...
Oh, and Lady Heather now speaks Star-4 management interface commands which are also used on a NEC GPSDO that shows up on Ebay... I have one of those on order.
> OSA8663: per year, 3.0E-8, in 10 years < 30.0E-8
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