Abstract: This paper proposes a phase noise model of ISF based on PSS+PXF to predict the phase noise of the oscillator. Compared with the traditional Lazavi model, the model takes into account the nonlinear time-varying characteristics of the oscillator, so it is more accurate. The effectiveness of the model is verified through simulation. The phase noise model precision of the ISF based on PSS+PXF is more than 200% higher than that of the traditional Razavi model.

Key words: oscillator high precision, phase noise, oscillator, impulse sensitivity function（ISF）, periodic steady state(PSS), periodic transfer function (PXF)