Thank you for your reply, there's still a question, after I tested every part of the PLL ,made models and put them together, how can I test the PLL's overall Jitter? Run pss+pnoise? But there seems no function in that PDF document, at the end of the pdf there is a example, but it only said "the period jitter of the PLL was found .....", I can't get to know "how to find?".
Maybe I should only test the VCO output Jitter?
And I saw the PD/CP jitter is 2ns , but the PLL jitter is 9.8ps, why?
It's my first time do this,so any reply is appreciated.