Frequency summing device

Device for summing two first and second sinusoidal signals of frequency F and f, respectively, comprising a first dephasing circuit receiving said first signal and providing a third signal whose frequency is F dephased 90.degree. in relation to the said first signal, a second dephasing circuit receiving said second signal and providing a fourth signal whose frequency is f dephased by 90.degree. in relation to said second signal, a first and a second analog multiplier each comprising two inputs, said first multiplier receiving on one of its inputs a signal whose frequency is F and a signal whose frequency is f taken from the group of signals constituted by said first, second, third and fourth signals, said second multiplier receiving at its inputs, the two remaining signals of said group, and an adder having inputs connected to the outputs of said two multipliers, characterized in that the frequency f varies in a frequency band centered on the frequency fo and in that said second dephasing circuit comprises a first elementary dephaser receiving on its input said second signal whose frequency is f and providing at its output an intermediate signal whose amplitude is equal to the amplitude of said second signal and whose dephasing in relation to the said second signal depends on the frequency f, that dephasing being equal to 90.degree. for the frequency fo, a second and a third elementary dephaser connected in series to the output of the said first elementary dephaser, an attenuator having an attenuation factor of 3 whose input is connected to the output of said third elementary dephaser, and an adder having two inputs connected to the output of the said first elementary dephaser and of said attenuator, respectively, and whose output provides said fourth signal.