Percentage of polarization intensity power lost when different band-pass filters are applied (first row) and ratios of the polarization S/N between the cases with and without band-pass filters (second row). The bandwidth of the filter Δf = (f_max−f_min)/2 is set to vary from 0.1 Hz to 5 Hz around the peak frequency (four times the rotation frequency). Plots are for a HWP spinning at 5 Hz (solid black line), 2 Hz (dotted red line) and 0.5 Hz (dashed blue line), for a telescope scanning at 12 deg/s and 0.7 deg/s.