vasu_lonka
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hi, i have done pnoise analysis using spectre on a sample and hold circuit( nmos used as the switch) . I have used a sampling frequency of 625KHz and signal frequency of 62.5KHz. Hold capacitor value is 14.5pF, which shuold give a total integrated noise power of 300p (kT/c). i used a maximum sideband value of 200. The thing Iam confused with is that if we choose stop frequency equal to 312.5KHz(fs/2), the total integrated noise is much less than kT/c . At the same time if we choose stop frequency equal to 1GHz the total integrated noise at the output equals the kT/c noise. Even though we used the maximum sideband options, we still need to integrate till very high frequencies. Can anyone please tell me why it is like this ?
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