Jitter simulation of Oscillator using HSPICE

[Rad_31]

jitter & hspice

How can i measure the output frequency and jitter of an oscillator using HSPICE , is it possible to get a graph of frequency verses time using transient analysis?

 

[Hughes]

You can do a transient analysis and use cosmosscope to calculate the frequency vs. time curve. You can also calculate the jitter directly by cosmosscope. But results may be over optimistic since hspice can't simulate transient noise.

 

[Rad_31]

Thanks!
I realised that its not possible to measure jitter using HSPICE.

I am trying to get the accumulated jitter from the phasenoise results in Spectre, however the integrated value of phasenoise is very large.Is it because the phase noise(dbc/Hz) values are negative?
Any idea how spectre computes the integral for a curve having negative values?