In the (very) few OCXO circuits I've seen, voltage at both ends of the tuning varactor are derived from the same internal voltage reference. So any drift in this will, partially at least, cancel out. I too was surprised to see nothing more than a Zener being used in one case, but bearing in mind this was in a temperature controlled environment is not as bad as a Zener in open air
Andy www.g4jnt.com On Sat, 25 Dec 2021 at 16:26, Poul-Henning Kamp <[email protected]> wrote: > Being also a bit of a volt-nut, I played a bit with the Vref output > from some of my OCXO's and must sadly report that they were not > spectacular, seen from a volt-nut perspective. > > In at least once case, an admittedly pretty old OCXO design, the > voltage reference was not located in the most well-regulated part > of the oven and the chosen chip had pretty bad tempco at the elevated > temperature. > > -- > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > [email protected] | TCP/IP since RFC 956 > FreeBSD committer | BSD since 4.3-tahoe > Never attribute to malice what can adequately be explained by incompetence. > _______________________________________________ > time-nuts mailing list -- [email protected] -- To unsubscribe send > an email to [email protected] > To unsubscribe, go to and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] -- To unsubscribe send an email to [email protected] To unsubscribe, go to and follow the instructions there.
