Main plot: comparison of the exactly known input periods P1_in and output periods P1_out for the noise-free case. The most significant period P1_out can be recovered fairly well. P1_out is on average 2.4% shorter than the actually contained period P1_in. Small plots: the distribution of P1_out is shown with increasing noise from top to bottom. For higher noise levels the fraction of periods lower than 0.5 cycles increases because the algorithm interprets the noise as short periods (compare Table 4).