Hi, I have a query regarding calculation of phase noise of VCO by pss and pnoise analysis.
From the phase noise plot it seems to me that is the PN of the 5th harmonic of the signal. is it right? If so, it should be the power of the 5th harmonic and the output noise at 7mhz of the same harmonic.
I looked at this a couple of weeks ago, and thought I'd responded - but it seems my reply didn't happen (there were some issues at the time - so maybe that's why).
Anyway, looking back through my notes, my example works fine. All that it does is look at the output noise using:
noise=value(getData("out" ?result 'pnoise)) ; "out" means output referred noisesig=harmonic(v("/vout" ?result 'pss_fd) 1) ; the 1 depends on the relative harmonic you chose when doing pnoise, the /vout depends on where you said the noise was to be measured
and then the phase noise (which is really output noise in dBc) is:
That's it. Nothing complicated. You're comparing the transient results - you should take a look at the pss results and ensure that the signals are as big as you think they should be. The numbers you're reporting sound very small, so something odd is going on here.
I would suggest you contact customer support if you're not getting anywhere.