Ken Kundert

No, you just average them. You just have to do it using power or power spectral densities.
In stationary noise, there is one type of correlation, correlation over time. That is responsible for coloring in the noise, or a variation in the noise power spectrum over frequency.
In cyclostationary noise there is also correlation over frequency, specifically the modulation frequency. When you sample the noise, you are sampling at the modulation frequency. As a result, the modulation disappears from the sampled output (you are sampling at the same phase of the modulation period, and so the modulation disappears). The resulting sampled noise is stationary, but it is still colored. It is fully represented by a simple powerspectrum. To get the timeaverage power spectrum of the entire waveform, you just have to average the power spectrums from each sample point. Of course, if the sample points are not evenly spaced you need to weight them accordingly. This is why I said you integrate the noise spectrums and then divide by the modulation period.
There is a lot of complexity to these calculations, but fortunately most of that complexity is hidden in the simulator and is being used to compute the sampled noise.
Ken
