Hi John, while I can't tell you which vendors are affected and which are not (Its like asking an angler for his secret angling spot :), I can say that most low cost TCXOs exhibit this behavior, and are thus not really suitable for GPSDOs. The ones we used on the LTE-Lite are quite good and do not exhibit this behavior. They are also 10x more expensive than the lost cost TCXOs in the exact same package that are typically used in non-critical applications. So far none of the quite reputable TCXO and OCXO vendors that I contacted about the problem can explain the behavior to me, like I said they were not even aware of the issue and had no way to test for it, and I had to prove it to them by sending our units to them so they can see the issue for themselves. Bye, Said In a message dated 10/21/2014 11:51:28 Pacific Daylight Time, [email protected] writes:
> Great insight thanks. You nailed it: out with the old oscillator and in with one > that doesn't have that problem. > > Btw the mechanical tuning issue you mentioned is essentially the same exact > problem: even the slightest turn will make the frequency jump too high or too > low. It can drive you (and the loop) crazy trying to get it on-frequency. Whenever I've seen this behavior, it has always been caused by uncertainty or "quantization" on the part of the trimpot's wiper, rather than anything that could be blamed on the varactor. What would be a good example of a TCXO or OCXO model that exhibits EFC hysteresis? I don't immediately understand what could cause this phenomenon, and I'd like to reproduce it here to see what's happening. -- john, KE5FX Miles Design LLC _______________________________________________ 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.
