yvkrishna
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Hi,
In the context of fractional plls, the nonlinearity in the PFD+CP transfer characteristic would result in noise folding which would increase the low freq phase noise.
I want to create a simple setup to capture in spectre simulations using 1.) quantisation noise by using zvcvs ( just by plugging coefficents of NTF of sigma delta modulator(z domain TF)) 2.) vcvs to create the nonlinear transfer char using pwl vector/data file (curve obtained from stand alone chargepump simulation charge Vs. delta phi (input phase difference))
If i cascade these two sources 1,2 can I really capture the folding effects(intermodulation )? but what simualtion (ac/tran/pac ) is needed for this kind of situation?
Ofcourse modeling modulator/chargepump in timedomain or using matlab for the same is fullblown exercise to capture it completely.
Thanks, yvkrishna
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