yeah, when i simulate xtal oscillator, i encountered the problem too. i'm confused, the pss voltage spectrum, (my osc is 32k)32k is much stronger than 16k, however, pss told me fundmental freq is 16K...
sometimes, i setup reltol to a small value, it works well, but sometimes, this mothod is useless
wakizashi wrote on Nov 20th, 2007, 5:17am:hi,
yes, tstab is enough because I can plot the waveform with started oscillation in pss-tran. the frequency of this waveform is 20MHz. there are no dividers in the circuit. only these 4 delay stages of ring oscillator.
pss-fd also shows 1 harmonic on 20MHz. but in log file I see that fundamental frequency found is half of this. Im not sure why this happens.
anyhow, thank you for the reply.