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Measurements >> Phase Noise and Jitter Measurements >> Crystal oscillator
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Message started by Danilo on May 23^rd, 2003, 1:43am

Title: Crystal oscillator
Post by Danilo on May 23^rd, 2003, 1:43am

I would like to simulate correctly a Crystal oscillator of 24MHz. Which parameters are important for the simulation? I have no problems of convergence but I do not know if the results are correct. The number of harmonics is important for the noise constribution, but anything more?

Thanks in advance

Title: Re: Crystal oscillator
Post by Dan Feng on May 23^rd, 2003, 4:26pm

In addition to the number of harmonics, errpreset is another important parameter. Try to compare results between errpreset=moderate and errpreset=conservative. They should be close. The parameter tstab is also useful. It enforces the simulator to do a stabilization transient integration before starting the shooting method. One can set saveinit=1 to save the waveforms in the stablization stage and see if things are pretty much settled at the end where shooting starts. In rare situation one needs to tighten the telerance (default = 1e-9) parameter for pnoise to get accurate solutions near the carrier.

Dan

Title: Re: Crystal oscillator
Post by jeffyan on Feb 28^th, 2004, 6:39am

hi Danilo:

if you do the simulation by hspice,please pay attention to correct option setting:
i.e method=gear,and ACCURATE and others.
what's more,in the trans. analysis,print precision is also important,(for f=24meg, "trans .1ns xx" is ok

by the way,you 'd better have a good model for crystal (turn crystal supplier for help).