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Crystal oscillator (Read 4711 times)
Danilo
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Crystal oscillator
May 23rd, 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
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Dan Feng
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Re: Crystal oscillator
Reply #1 - May 23rd, 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
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jeffyan
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Re: Crystal oscillator
Reply #2 - Feb 28th, 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).
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