Hi all,
      I want to simulate the output phase noise of a XOR based frequency doubler. The input is 20MHz signal. I follow the step in the paper"Predicting the Phase Noise and Jitter of PLL-Based Frequency Synthesizers" about simulating divider phase noise. The pss fundamental frequency is 20MHz. There are two crossing points in a 20MHz period. I want to simulate the one crossing point in a 40MHz period. It seems impossible to simulate the 40MHz phase noise in time domain. How should I do to get the accurate phase noise of the 40MHz output?