Abstract: A digital phase and amplitude modulator with a code conversion circuit having several digital inputs able to receive digital data and the same number of outputs supplying code converted digital data, a generator of at least one carrier having at least one phase control input and at least one output supplying at least one carrier having a given phase, a digital-analog converter comprising a first stage formed by logic gates having two inputs and one output, one input each of the logic gates being connected to one of the outputs of the code conversion circuit, while the other input is connected to one of the outputs of the generator, and a second stage formed by the same number of transistors as there are logic gates.

Abstract: The invention relates to a circuit for controlling the cyclic ratio of a periodic pulse signal.This circuit comprises a monostable multivibrator receiving the pulse signal at its switching input, a comparator constituted by an operational amplifier respectively receiving at its inputs the direct and complementary output signals of the monostable multivibrator, the output of said amplifier being connected to the conducting period control input of the multivibrator. The operational amplifier also comprises a control input for the offset voltage of the signals applied at its inputs, said control input making it possible to regulate the cyclic ratio of the multivibrator output signals.Application to frequency multiplication, particularly for four-state modulation by phase displacement.