[time-nuts] Square to sine wave symmetrical conversion

[Bob Camp]

Hi


> On Jul 27, 2015, at 1:28 PM, Charles Steinmetz <csteinmetz at yandex.com> 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.

Ok, *but* that’s really an issue with a *destination* circuit rather than the *feed* circuit. What they are talking about are 
zero cross errors rather than phase noise. Put another way:

Phase noise is L(f)
What they are talking about are time errors. 

Bob

> 
> 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>
> 
> 
> 
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