The Designer's Guide Community Forum

The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl
Simulators >> RF Simulators >> Oscillator Phase noise analysis
https://designers-guide.org/forum/YaBB.pl?num=1114127149

Message started by ganesh on Apr 21^st, 2005, 4:45pm

Title: Oscillator Phase noise analysis
Post by ganesh on Apr 21^st, 2005, 4:45pm

Cyclostationary noise processes are accurately characterized by time varying power spectral density.

In some cases just time average power spectral density is sufficient to characterize the cyclostationary noise, while in other cases it is not the case.

My question is for Oscillator phase noise analysis is it sufficient to characterize a colored cyclostationary noise by its time average power spectral density ?

Thanks,
Ganesh.

Title: Re: Oscillator Phase noise analysis
Post by Frank Wiedmann on Apr 22^nd, 2005, 5:40am

The noise of a free-running oscillator close to the carrier is almost pure phase noise (see section 3 of http://www.designers-guide.org/Analysis/PLLnoise+jitter.pdf). This means that for low spectral frequencies, the variation over time of the cyclostationary noise in V/sqrt(Hz) will be almost perfectly proportional to the absolute value of the slope of the oscillator signal. With this knowledge, you should be able to reconstruct the time-varying power spectral density of a free-running oscillator at low spectral frequencies from its average power spectral density.