Hi At some point you must go “inside” the loop (or your OCXO isn’t locked …). At that point, you run into the basic physics of frequency multiplication.
Bob > On Nov 30, 2021, at 7:16 PM, Matt Huszagh <huszaghm...@gmail.com> wrote: > > Jürgen Appel <j...@dfm.dk> writes: > >> Yes, this is a fundamental physical property which cannot be avoided. >> >> You can see it that way: If there is a given fluctuating time delay in your >> otherwise perfect 5 MHz signal, the amount of phase shift this time >> fluctuation corresponds to in a 10 MHz signal is simply twice as big as in >> the >> 5 MHz signal, simply because the phase evolves twice as fast at 10 MHz. >> >> This factor of two makes up the 6dB in noise power. >> >> If you divide the 6 dB noisier 10 MHz signal down again, (neglecting >> additional technical noise), you get the original performance of your 5 MHz >> signal back. > > Doesn't this assume that you inherit all the noise of the reference? For > example, the short-term stability of a GPS 1PPS signal is poor, but you > can still use it to discipline a VCO with much better short-term > stability and retain most of the short-term stability of the VCO. > > Matt > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an > email to time-nuts-le...@lists.febo.com > To unsubscribe, go to and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
