Averaged noise PSDs for each detector (upper curves) and correlated-noise modes for each polarized horn (lower curves). The total noise power is the sum of the correlated and uncorrelated modes. These noise PSDs are measured from the data by subtracting a signal estimate and then evaluating the sample-sample covariance function. The HFI noise is suppressed near the Nyquist frequency (≈90 Hz) by the bolometric transfer function filtering. The PSDs are used for simulating the 1/f noise fluctuations, and as inputs to the Madam noise filter for destriping.