A couple of disclaimers here: 1. Leeson's oscillator model was mentioned. That doesn't apply much to crystal oscillators. The close in noise will be limited by the intrinsic noise of the crystal and the far out noise will be limited by the buffer amplifier. Leeson's model never comes into play. BTW, the intrinsic noise of the crystal is higher than the thermal noise corresponding to its ESR, at least below 1 kHz or so.
2. Using crystal filters to clean up after the fact is limited by the intrinsic noise of the crystals in the filters. Hence, this usually only makes sense if you multiply a xtal oscillator then filter, as in the HP8662, and then it only improves the noise floor. Unless you have access to very low noise crystals, you are not going to get very far building your own oscillator. Rick Karlquist N6RK _______________________________________________ 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.
