Hi Just so this does not get to ghastly confusing for those trying to follow along:
Vig, John R.; Ferre-Pikal, Eva. S.; Camparo, J. C.; Cutler, L. S.; Maleki, L.; Riley, W. J.; Stein, S. R.; Thomas, C.; Walls, F. L.; White, J. D. (26 March 1999), IEEE Standard Definitions of Physical Quantities for Fundamental Frequency and Time Metrology – Random Instabilities, IEEE, ISBN <https://en.wikipedia.org/wiki/International_Standard_Book_Number> 0-7381-1754-4 <https://en.wikipedia.org/wiki/Special:BookSources/0-7381-1754-4>, IEEE Std 1139-1999 On page 2 defines phase noise as: ℒ(f)=Sφ(f)/2 where the "phase instability" Sφ(f) is the one-sided spectral density of a signal's phase deviation. (Yes, that’s a bit of cut and paste from Wikipedia. I believe that their citation is correct.) Put another way, it’s what a phase noise test set measures (HP 3048 or whatever). It’s also the part of the spectral noise (as opposed to AM noise) that goes up as 20*log(N) when you multiply the signal’s frequency by N. Phase jitter and cycle jitter are not the same quantity. Bob > On Jul 27, 2015, at 1:28 PM, Charles Steinmetz <[email protected]> wrote: > > Bob wrote: > >> In tis case the question is "do you *need* low harmonics in the oscillator >> stage to get low phase noise?" > > Note that there are actually two questions. One is WRT the phase noise of > the oscillator itself, and the other WRT the phase noise of a system that > integrates the oscillator. In particular, even harmonics in the oscillator > proper generate additional phase noise in the system when the signal is > AC-coupled and/or DC-restored, and when it is fed to a zero-cross detector or > other circuit that is sensitive to the symmetry of the waveform. > > NIST published a paper on this.[1] There is other research describing and > quantifying the phenomenon, as well. > > Best regards, > > Charles > > > [1] "The Effect of Harmonic Distortion on Phase errors in Frequency > Distribution and Synthesis," Walls and Ascarrunz > <http://tf.nist.gov/timefreq/general/pdf/1437.pdf> > > > > _______________________________________________ > 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. _______________________________________________ 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.
