Patent ID: 7280003

Claim:
A signal modulation device comprising: one input channel for a high-frequency signal (P 0 ); two input channels adapted to deliver analogue phase-modulation signals with constant amplitude, in phase and in quadrature, respectively; an input channel comprising a delta-sigma modulator arranged for receiving an analogue amplitude-modulation signal at its input and for delivering a pulse signal at its output; and a mixer having inputs respectively connected to the input channel of the high-frequency signal, to the input channels of the phase-modulation signals, and to the output of the delta-sigma modulator, said mixer being arranged for producing, at its output, a signal substantially proportional to a subtraction between: on the one hand, a first signal equal to the in-phase analogue phase-modulation signal multiplied by a first sinusoidal carrier signal and by the pulse signal, and on the other hand, a second signal equal to the in-quadrature analogue phase-modulation signal multiplied by a second sinusoidal carrier signal and by the pulse signal, wherein the mixer comprises: a phase-shifter connected to the high-frequency signal input channel and adapted to produce at two respective outputs said first and second sinusoidal carrier signals with quadrature phase shifts relative to each other; a multiplier connected by respective inputs to the output of the delta-sigma modulator and to the outputs of the phase-shifter, and adapted to produce, at two outputs of said multiplier, signals proportional to the pulse signal multiplied by one of said first and second sinusoidal carrier signals, respectively; and a phase modulator having two first inputs respectively connected to the input channels of the phase-modulation signals and two second inputs respectively connected to the outputs of the multiplier.