How to simulate the SNR of a Sigma-delta modeulator

[ken_cn]

Hi
I have worked out a sigma-delta modeulator, but I do not know how to evaluate its performance. Could you tell me how to get the SNR, by Hspice or Matlab are both ok. Thank you!!

Ken

 

[sunking]

.tran
then do fft analysis.

or
.pss
.pac
.pnoise
by sepctre

 

[ken_cn]

thanks Sunking!
But how to choose the number of fft pionts. and how to calculate the snr from the fft result?
Thanks!