I think I have a flaw in my understanding of this. How can something like an SR620 measure the ADEV of an oscillator, if the oscillator is of a similar or better than the reference fed into the SR620?
I see plots of ADEV for hydrogen masers, but I can't understand how this can be measured from the phase data unless the reference is better than the DUT, which is not going to be possible with a good hydrogen maser. I was thinking it might be possible if one has 3 oscillators and 3 time interval counters to perhaps solve 3 simultaneous equations. I can't prove that, but it seems intuitively correct. I must be missing something! Also I have seen graphs of both Allan variance and Allen deviation. Both are typically 10^-12 for a decent oscillator, but given the variance and standard deviation are related by a square root, they can't both be around 10^-12. I would expect to see values of 10^-6 or 10^-24, but I don't see such dramatic differences from 10^-12. If I see numbers around 10^-12 on an OCXO, is that the Allen variance or Allen Deviation? Dave _______________________________________________ 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.
