Orbital period distribution of the 65 SDSS PCEBs discovered in an homogeneous way through radial velocity variations measured in spectra spread over different nights (grey) and the bias-corrected distribution (white). The Gaussian fit to the bias-corrected distribution is plotted with a dashed line. In the upper panel we show the mean probability of detection as a function of the orbital period (see text) and the corresponding mean value at each bin centre (red dots).