Phase noise (dBc/Hz): -18 KHz and -74 KHz For a relative Harmonic 1, maximum sidebands 20 and a Beat Frequ equal to my oscillation frequ, I get the following results from pnoise analysis: My PSS gives me a differential voltage peak to peak amplitude of 250 mV.
I have more questions, but I will give you numbers this time to be more exact. I haven't resolved yet the corner frequency issue. This is what you get when you ask for "phase noise" when using the basic PNoise analysis (when you have not gone to the trouble of specifically asking Spectre to compute the PM and AM components to the noise). So if P out is the output power and you can model the noise with a/(1+ f c 2/ f 2), then you solve for a by matching the model to the noise at frequencies above the corner, and then you solve for f c using P out = a/(1+ f c 2/ f 2).Īrtist does compute L, the normalized noise. You can estimate the corner frequency by using the fact that the total area under the noise curve must equal oscillator output power (noise in phase does not add power to the signal, it simply redistributes the power in frequency).
#Cadence plot one waveform divide another simulator#
Thus it is not just Cadence's simulator SpectreRF that has this characteristic, it is shared by all commercial RF simulators.
Just so we are clear, the inability to compute the corner frequency is a weakness shared by all simulators that use small-signal assumtions in their noise analysis.
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