Thank you for the reply. I read the postings you had mentioned but it somehow didn't solve my problem.

**Quote:**For time-domain noise (noisetype=timedomain), SpectreRF calculates the PSD of the discrete (or sampled) noise at t0+n*T (T=1/PSSfund, 0<=t0<=T, -infinity<n<+infinity)

This corresponds to what I believe the PSD of the sampled output noise of a system would be which provides one output sample every 1/PSSfund. E.g. the switched cap. in K. Kunderts document 'Simulating Switched Capacitor Filters with SpectreRF'

The system I am looking at provides output samples at a rate 1/(4*PSSfund) does that not mean that spectre undersamples the output noise when the PSD is sampled at PSSfund (instead of 4*PSSfund)?

From my understanding the output noise in TDPnoise should be band-limited from 0..4*PSSfund/2

Thank you.