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Measurements >> Phase Noise and Jitter Measurements >> Cyclostationary or Stationary?
https://designers-guide.org/forum/YaBB.pl?num=1117754437

Message started by samadian on Jun 2^nd, 2005, 4:20pm

Title: Cyclostationary or Stationary?
Post by samadian on Jun 2^nd, 2005, 4:20pm

It is widely assumed oscillators are cyclostationary (This appears in Ken's paper "An Introduction to cyclostationary noise" as well.)

Demir's famous paper however claims noisy oscillators are stationary. This makes a huge difference in modeling phase noise, so which one do you believe is correct? ???

Thanks....Sohrab Samadian, UCLA

Title: Re: Cyclostationary or Stationary?
Post by Ken Kundert on Jun 2^nd, 2005, 10:29pm

Sohrab,
Check out page 32 of http://www.designers-guide.org/Theory/cyclo-preso.pdf.

-Ken

Title: Re: Cyclostationary or Stationary?
Post by samadian on Jun 2^nd, 2005, 11:02pm

Thank you Ken, that was enlightening...

So in a typical RF circuit noise generated by oscillator is cyclostationary and time-average power spectral density can not be used to calculate noise power at osc. output.

Then, if there is a cyclostationary noise source present in an oscillator, how does one calculate output noise power to see it's effect on phase noise? It's not time average of PSD, any clue how to approach this?

I love this website!! In America nothing is free... seems like not in here though... anyway, thanks for your time

Title: Re: Cyclostationary or Stationary?
Post by Frank Wiedmann on Jun 2^nd, 2005, 11:50pm

The term "phase noise" is not really very well-defined, see http://www.designers-guide.org/Forum/?board=jitter;action=display;num=1036850366;start=. If you are really interested in jitter rather than phase noise, you should probably use the strobed noise analysis of SpectreRF. This has been discussed at some length in the thread starting at http://www.designers-guide.org/Forum/?board=rfsim;action=display;num=1092399689;start= (make sure to look at all 3 pages).

Title: Re: Cyclostationary or Stationary?
Post by Ken Kundert on Jun 3^rd, 2005, 8:55am

Sohrab,
The time average PSD combines both the AM and PM components of the oscillator noise. Generally in the range that is of greatest interest, the noise produced by an oscillator is almost purely phase noise. In this case, the time average PSD is the phase noise.

-Ken