Abstract: Synthesizer of multifrequency signals for telephone sets, each multifrequency signal being formed by two concomitant sinusoidal signals of different basic frequencies, said frequencies forming pairs respectively corresponding to the decimal digits and being sub-multiples of a common clock frequency. The sinusoidal signals are pulse trains whose repetition rate varies steppedly in function of time in the following manner. The period of a sine function is divided into p parts and the amplitude of the function taken from the tangent to the negative peaks of the sine curve for p equidistributed values of the argument 2.pi.i/p, i varying from l to p, are approximated by p amplitude values. The periods of the signals having the basic frequences are divided into p time intervals and during these time intervals, a pulse train generator is operated in such a way that its pulse repetition rate be proportional to said amplitude values.