On 2021-03-31 14:27, Richard (Rick) Karlquist wrote:
When I left Keysight in 2014, they were still trying to solve the microphonic problem in their sapphire resonator oscillator. Also, it is still necessary to lock the oscillator to a 5 or 10 MHz OCXO. The oscillator is tuned by varying its oven temperature set ppoint.
What kind of oven temperature range? I thought sapphire oscillator was pretty much synonymous with "cryogenic sapphire oscillator." I found a paper which described sapphire as a "low loss material with loss tangent of 5×10^−6 at room temperature, 2×10^−8 at 77 K and 7×10^−10 at 4 K giving Q-values of more than >10^7 at low temperatures."
That paper seemed to be describing some kind of temperature compensation they had developed to reduce the temperature sensitivity of 10ppm/K and also move the turnover point from 77K to 92K. 92K isn't exactly what I think of when I hear "oven" so presumably there is some mode that works at around 300K that I didn't find discussed yet.
-- Chris Caudle _______________________________________________ time-nuts mailing list -- [email protected] -- To unsubscribe send an email to [email protected] To unsubscribe, go to and follow the instructions there.
