RECEIVER OF AN ELECTROMAGNETIC SIGNAL WITH A KNOWN NOMINAL FREQUENCY, LIABLE TO BE AFFECTED BY AN UNKNOWN VARIATION, IN PARTICULAR BY THE DOPPLER SHIFT

摘要

The invention concerns a feedback control loop comprising a mixer comprising a first input receiving an electromagnetic signal, and a second input receiving a first local signal; an intermediate frequency line mounted between the output of the mixer and the input of a phase comparator which receives on a second input a second local signal and has an output; and a feedback line connected between this output and the second input of the input mixer, and comprising a loop filter controlling a variable oscillator for providing the said first local signal as well as a second variable oscillator for providing the second local signal. The loop filter comprises (i) a proportional section mounted between the output and the control input of a second variable oscillator; (ii) an integral variable section mounted between the output of the proportional section and the control input of the first variable oscillator; and control means capable of progressively changing the parameters of the proportional and integral sections so as to progressively reduce the bandwidth of the phase control system and to increase the filtering of the noise and of the interference signals superposed on to the electromagnetic signal.