I am simulating a very simple integrate and dump filter to correlate the results for Pnoise simulations. it just consists of resistance and capacitor being charged by current source and they are periodically shorted to ground.

What I am trying to see is that the noise power due to resistor which is very large (it should be around 1P=10e15 ohms) is indeed proportional to the integration time. My thinking is that I need to sample the output at the right point in noise simulations using time domain noise simulation in PNOISE analysis, ideally just before the end of the integration period and look at the PSD of that noise. Is that the right way to simulate the output noise current due to thermal noise the resistor?

Thanks for any pointers.