Hi Then there's the phase noise of the pulsar "oscillator" ....
------------------------------------- For a simple crystal oscillator the two word answer might be "Leeson's model". That of course is a cop out since it clearly defines multiple things that contribute to phase noise. Bob On Mar 5, 2010, at 9:39 AM, Richard (Rick) Karlquist wrote: > Don Collie jnr wrote: >> I`m not sure that questions like these is welcome on this list, but here >> goes anyway : 1/ What are the the 10 sources of the most constant >> [invariant] frequencies known to man, in order of decreacing constancy? Four >> immediately come to mind. > > I vaguely remember reading that pulsars have some fantastic > stability like 1E-20. I don't remember how they established > this. > >> 2/ What is the mechanism in an oscillator, that is responsible for phase >> noise? [In only one sentence please] > > Thermal (Johnson) noise in the resonator and thermal and shot noise in the > active device. > >> If this is known, then it becomes easier to design low phase noise >> oscillators. > > Perhaps, but just knowing the mechanism doesn't tell you that the > phase noise is inversely proportional to loaded Q, which you would > also need to know to optimize phase noise. > > >> I hope you enjoy these questions,.................................Don. >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
