acezhy
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Posts: 10
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Hi all :)
In order to correlate PLL's phase noise with a measured one from E5052, I need to simulate the phase noise of an output logic divider with SpectreRF. Unfortunately, the logic divider biased from a noisy power would introduce much AM noise, which cannot be simulated with PSS+PNOISE by setting 'noise type=sources'. As such, I simulated its phase noise by 2 ways: 1) Setting 'noise type=modulated', I got a so-called PM noise (dBc/Hz) from it. 2) Setting 'noise type=jitter', I got a voltage noise spectrum (tdnoise) at the threshold voltage. Mutiplying this result by 2*pi*fo and dividing it by the slope at the threshold voltage, a phase noise curve is achieved.
By comparing the PM curve and the calculated one, there exists a large deviation between them and their shape is not unique either. My questions are: 1) Which one of the 2 curves is the phase noise which could be compared with the measured result? Or I have made a mistake? 2) Does the PM noise could be used to describe the phase noise of a logic divider? Or it is only valid for oscillator?
Any reply is appreciated Thanks!
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