didac wrote on Jul 19th, 2008, 3:43am:For the transient simulation I will think a little bit how to do it because the oscillator it's at 5GHz and we are seeing this periodic behaviour in the order of seconds(we see it in a spectrum analyzer and you can count with your fingers the time that last to change from the original frequency to the "secondary" one) so maybe I will need to book for the Mare Nostrum supercomputer for disk space...
If you have Agilent GoldenGate simulator, try envelope analysis. Or try envelope analysis of Agilent RFDE(ADS).
A perfomance of envelope analysis of GoldenGate is very superior than RFDE(ADS) analysis engine.
I don't know a perfomance of envelope analysis of current Cadence Spectre.
Since envelope analysis of old Spectre was ultra very slow and wasn't practical use level at all, so a thinking of trying envelope analysis of Cadence Spectre does not rise in my mind even now. It could result in a waste of time.
Even if you apply envelope analysis of Agilent GoldenGate or RFDE(ADS), you have to tune simulation set up for getting reasonable results and running envelope analysis effectively.
If separation of two frequencies is fairly large, you should invoke two tone envelope analysis.
Even if separation of two frequencies is relative small and then you invoke one tone envelope analysis, there are three options about choosing nominal frequency.
(1) Lower oscillation frequency
(2) Upper oscillation frequency
(3) Average frequency of above two