Top left panel: power spectrum of SMEI observations between frequencies f1 and f3 (Table 5). Top right panel: as top left, except for combined SMEI and BRITE data. Other four panels: power spectra of a single sine function with frequency f2 evaluated at SMEI observing times. This variation is modulated with different amplitudes (A) and frequencies (F). 0.0003125 c/d is about the inverse of the time span of the SMEI observations. Middle left panel: A = 10 km s⁻¹, F = 0.0003125 c/d; there is almost no difference w.r.t. the SMEI observations. Middle right panel: A = 30 km s⁻¹, F = 0.0003125 c/d; the strength of the side lobes increases with the amplitude. Bottom left panel: A = 20 km s⁻¹, F = 0.0003125 c/d; bottom right panel: A = 20 km s⁻¹, F = 0.000625 c/d. The separation of main peak and side lobes increases with modulation frequency.