Hi I don’t really see anything in your plots that looks like it correlates with temperature. You may have processed it out with some of your fitting and regression stuff.
There *is* something going on with he red line. What it is … very unclear. Best guess would be a bum solder joint somewhere. Pretty much all of these OCXO’s (regardless of seller) come out of a pretty brutal scrap process. It is “normal” to get more bad then good when you buy a group of them. Generally, the closer you look, the more you throw out. That’s been true for quite a few years now. Bob > On Apr 25, 2019, at 11:43 AM, Bob Quenelle <[email protected]> wrote: > > In testing a new OCXO, I found it had more drift than a previous one. I'm > happy with the better one, not so much for the poorer one. I'd like get some > opinions on whether the performance of both seems reasonable. > > I bought both from a US seller. They’re UCT 108663-01, a double oven OCXO. I > didn't specifically want DOCXO, just had mixed experience with China-based > sellers and decided to try a US seller. Both have over 100 hours of run > time. > > To compare the 2 OCXO's I let both OCXO's and an LPRO-101 run for about 12 > hours to stabilize. Then I turned off DAC updates so the control voltage was > constant and collected phase of each OCXO relative to the LPRO-101 every 10 > seconds. I subtracted successive samples and scaled to get mHz. Next I > subtracted the linear regression line so I could see deviations from > nominal. I also used exponential averaging with factor 0.1 to clean up the > noise. I'll attach the graph and see if it makes it through. In summary, > over the 6 hour run the better OCXO shows a peak to peak deviation of 0.2 > mHz and the poorer one showed 0.9 mHz. This is deviation/wander from > nominal, not overall drift. The graph also shows room temperature. > > I've run a test with both OCXO's in the same box on different days and seen > similar results so it's not the voltage reference or DAC. I show this test > because both OCXO's ran at the same time. > > <OCXO_1.JPG>_______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
