The invention relates to a random clock generator comprising an input receiving a master clock signal MCIk, and a clock signal reduction circuit (101) receiving the master clock signal MCIk and a whole number N and supplying an output signal corresponding to a train of N pulses every M clock pulse, M being a whole number higher than 1 and N being a whole number higher than 1 and lower than or equal to M. A number generator (102) and (103) supplies a new number (N) to the clock signal reduction circuit every P pulse of a master clock signal, N and/or P being produced randomly.