Hi!

I am attempting to simulate the phase noise of an LC CMOS VCO, that is influenced by a switched capacitor network running at another frequency.  For the sake of this point, maybe consider it as an oscillator with a input signal in the topology - hence appearing non-autonomous to spectreRF.  How would you simulate the phase noise of this system?

Thank you!

Hi Gavi,
thanks for your input.  Unfortunately, only PSS takes autonomous oscillation as an input.  

My intuitive solution is to do a PSS without the external signal to obtain the oscillation frequency, then add another very small signal sinusoidal input at that frequency to some reasonably insensitive node.  Then run QPSS using the external source and the new small signal source as inputs.  One potential problem here is frequency shifts - pushing/pulling - due to the effect of the external source making the frequency of the new signal source inaccurate, so I'm not entirely satisfied with the solution.