Frank. I appreciate your help. Your replies were really helpful.

Unfortunately, I still have some questions. Can you give me more answers?

1. From your suggested documents, meaningful jitter for autonomous circuit is Jc.

However in 10page "Jitter measurements using SpectreRF application note" by Cadence, Jc is timing difference between ideal reference  and output.

There is no reference OSC in case of VCO. From definition the meaningful jitter of VCO is Jss, isn't it?

2. And you said that one should make jitter property as PM jitter not FM jitter for autonomous circuit.

However I can't do it. It is selected automatically. How can I change the jitter property in analysis setup.

3. If all blocks in ADC are drived by VCO, how can I choose k the number of cycle? If I choose k higher than 1, the accumulated jitter increase infinitely.

4. What I really want to know is the method to calculate jitter by spectreRF.
Therefore I orginized a flow as below.
>> Direct plot >> Main form >> pnoise jitter >> jc or jcc >> define integration range >> plot

However there is a problem, you said the frequencies fc and fo do not affect the integration.

But the calculated jitter value is varied too much with the integration range.

Is there no correct method to calculate jitter by spectreRF?