Re: [Moved]:[Cadence Virtuoso ADE Calculator] Difference btw Freq and Frequency Funct
In this case, I don't understand what the steady state is for a ring oscillator.
Until it can reach steady state, both amplitude and period will be varied.
Study "Autonomous-Shooting-Newton-PSS" of Cadence Spectre.
It checks amplitude and period as Shooting Trial Intervals.
2. "(delta_f/2)/f0*100=0.016%" => What is the purpose of this calculation?
I mean frequency pertubation during transient is very small.
I'm not sure what phase noise has to do with oscillation frequency,
or am I probably misunderstanding something?
Can you understand Transient-Noise Analysis ?
Transient-Noise Analysis is available in both Cadence Spectre and Synopsys HSPICE.
However I think you do conventional Transient Analysis without Noise.
So phase noise is not concerned for your case at all.
5. I increased the time to 100ns, and still see the similar perturbation
Tighten simulation accuracy.
If you use Cadence Spectre, set "errpreset=conservative".
If you use Synopsis HSPICE, set "RUNLVL=6" or use HPP(HSPICE Precision Parallel).
Or set small value as "maxstep" of Cadence Spectre or "delmax" of Synopsis HSPICE.
For example, (1.0/16G)/100.0.