Top panels: residual auto-spectra of the ADCNL at 100 GHz, for a single simulation (purple line), after correction by the gain variation model. An average over five realizations is shown as the blue line. Using the difference, and scaling it as Gaussian noise for one simulation, we then subtract it from the single simulation (purple). The red curve shows the residuals when removing this estimate of the noise. Bottom panels: the residuals for the four frequencies.