Andrew Beckett wrote on Mar 22^nd, 2010, 8:29am:
Yes.

Andrew Beckett wrote on Mar 22^nd, 2010, 8:29am:
Fourier Series Expansion requires fundamental period value for calculation which we want to evaluate.

This is also true for Fourier Transform.
If we don't have much frequency resolution, we could miss true long fundamental period.

Of course, this resolution issue is true for auto-correlation evaluation.
But regarding detection of periodicity, auto-correlation Analysis is superior than Fourier Analysis,
since we don't have to put importance in an accuracy of amplitude value for auto-correlation.

The most practical and sensitive method I have found for checking periodicity with a circuit simulator is to use strobing and set the strobe period to the expected period. Then run a transient simulation for many cycles and plot the results. Look at the waveforms at a variety of nodes. A particularly good signal to look at is the supply current. If they all become constant valued, then the system is periodic in the given period. I have used this method to find subtle oscillations and small amounts of chaotic behavior for dead-zones that have prevented convergence of PSS.

But again, I only do this to determine why PSS is not converging. I have always found that if PSS converges, you have the right period.

-Ken