Hi If ADEV was a “narrowband” measure, you would be correct. Unfortunately ADEV looks at a wide range of frequencies so doing a single point analysis can be misleading. However the general conclusion is often correct in the case of simple noise processes.
One way to “get better” is to look at phase noise at 1 Hz or at 0.01 Hz. You then have a narrowband measurement. Indeed you can say that the phase noise at 0.01 Hz isn’t going to get below the best phase noise of the two sources. That *is* correct in all cases that I know of. Another approach is to use the Hadamard variance. It is a bit more “narrowband” and is a bit more useful for crossover analyses. It’s still not as accurate as using phase noise. Bob > On Apr 19, 2019, at 10:00 PM, Anton Moehammad via time-nuts > <time-nuts@lists.febo.com> wrote: > > Hi Everybody,excuse me for asking this question. > 1. Let say I have a GPS receiver with 10 E-12 at Tau 100 second and I use it > in GPSDO to control OCXO with 10 E-10 at Tau 100 second.The best I can get > from this setup is 10 E-12 at Tau 100 second is this correct ? no matter how > long I run my GPSDO (I disobey another factor that can influence stability) > Thank YouAnton > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
