Transformation of a periodic signal into an adjustable-frequency signal

A device for transforming a periodic input signal into an output signal of distinct frequency, comprising two adjustable delay means receiving the input signal, a multiplexer selecting the output signal of one or the other of the delay means, control means for, according to whether the output signal frequency must be smaller or greater than the input signal frequency, increasing or decreasing at the rate of the input signal, or at a multiple of this rate, the delay of the selected delay means, and controlling a minimum or maximum delay for the delay means which has not been selected, and a phase comparator adapted to changing the multiplexer selection when the transitions of the signals output by the delay means corresponding to a same transition of the input signal are offset by a duration greater than or equal to one period of the input signal.