Abstract: A limiter circuit having a field effect transistor whose bias circuit is constituted by two constant voltage feeds: one for its gate and the other for its drain, with a resistive load being connected in series with the feed to the gate of the transistor. The invention is particularly applicable to space telecommunications.

Abstract: A method of forming the radiation pattern of a high efficiency active antenna for electronically-scanned radar, wherein its illumination laws, and thus its radiation patterns are dissociated in transmission and in reception; and equal amplitude illumination is provided in transmission in order to maximize the efficiency of the transmit amplifiers which are all identical, thereby minimizing their DC energy consumption and their dissipation. The invention is particularly suitable for use in space radars.

Abstract: A phase loop demodulator, in particular for space telecommunications, comprises a primary phase loop, a locking detector circuit responsive to acquisition by the primary loop, and a secondary phase loop controlled by said detector circuit.

Abstract: A Costas loop carrier recovery device with particular application to communications with spacecraft includes a voltage-controlled oscillator. Two filters having different characteristics are connected to the oscillator by a loop filter via two circuits:a direct connection, anda parallel circuit including an amplifier in series with a filter.

Abstract: A geostationary telecommunication satellite has a platform pointed towards the sun and a payload that is rotatable so as to point always toward the Earth. A method of placing this satellite in its final orbit entails using the inertia wheel of the satellite together with its sensors and possibly its two-axis rate gyro to secure attitude control of the satellite during the transfer, that is while in the transfer orbit and during the apogee burn.

Abstract: A power supply module for control electronics of a DC motor, the module comprising a power cell of the stepdown type controlled as a function of peak current, the current flowing in both directions, and the module including a bridge stage likewise capable of passing current in both directions and including a reactive element constituted by one of the windings of the DC motor. The invention is particularly suitable for space applications.

Abstract: A diplexing radiating element comprising at least a first radiating element in which two radiating electrical currents flow which are spaced apart from each other, and at least one second element in which two radiating magnetic currents flow which are spaced apart from each other. The invention is particularly applicable to space telecommunications.

Abstract: The invention relates to a space reentry vehicle high-temperature skin antenna comprising a printed antenna embedded in a tile for providing thermal protection, and fed by electromagnetic coupling. The invention is particularly applicable to space telecommunications.

Abstract: An electronically scanned antenna comprising an array (11) of elementary sources, an energy-focusing reflector (10), and feed and control electronics, with the array (11) being situated in the focal zone of the reflector, and in which elementary sources that are not used simultaneously are grouped together in classes (Ci) in which only one source can be active at a time, with all of the sources in each class (Ci) being interconnected by a passive combiner (40) for that class. The invention is applicable in particular to space telecommunications.

Abstract: A circuit for regulating an electrical parameter to be servo-controlled by transferring electricity between two networks (11, 12), wherein the circuit (10) is a bidirectional current circuit providing electrical isolation between the two networks (11, 12). The circuit is particularly applicable to space applications.

Abstract: A filter having a dielectric resonator, the filter comprising at least one cylindrical cavity (10) inside which there is a dielectric resonator (11) whose axis of symmetry (.DELTA.) is colinear with the axis of symmetry of the cavity (10), the filter being characterized in that the resonator is held by a system of dished washers (15, 16). Applicable to microwave frequencies.

Abstract: A device for exciting a waveguide with circular polarization from a plane antenna, said waveguide (10) being a rectilinear hollow waveguide closed at one of its ends (12), said antenna being excited by at least two coaxial ports (13, 14) fed in phase quadrature by a circuit including a hybrid coupler (15), and being constituted by a radiating plane metal pattern (11) disposed on the surface of an insulating substrate (18) closing the waveguide (10) perpendicularly to its axis of symmetry.

Abstract: The present invention relates to a two-frequency radiating device comprising a waveguide radiating in a first frequency range opening out into a radiating element operating in a lower, second frequency range. The invention is particularly applicable to antennas.

Abstract: A method of digitally evaluating the frequency and the phase of signals in the form of digitized samples, the method being wherein it comprises in succession:a stage during which numbers corresponding to the samples of the signals to be analyzed are processed in order to convert them into the form of an analytic signal whose real portion coincides with said signal to be analyzed; and, in parallel therewith:a stage of estimating the parameters to be analyzed which is performed in an overall manner on the basis of estimators and of selection criteria by working on the phase of the signal without using any operator of the Fourrier transform type of any hypothesis test either separately or simultaneously; anda stage of estimating the differences between the real signal as taken in this way and the signal obtained from the estimated parameters, thereby making it possible to deliver data in digital form relating to the quality of the analyzed signal and to the reliability of the estimated values.

Abstract: The present invention relates to an antenna which is electronically reconfigurable in transmission. The antenna comprises an array (11) of elementary sources, an energy-focusing reflector (10), with the array (11) being situated in the focal zone of the reflector, and control and feed electronics, the electronics comprising an amplifier stage (22) constituted by amplifiers (24) and including at least one generalized coupler disposed at the outputs of the amplifiers (24), and beam-forming circuits (20, 21) each corresponding to a transmitted beam, with the amplitude and relative phase of the signals leaving said circuits being controlled by respective adjustable phase shifters and adjustable attenuators. The invention is particularly applicable to space telecommunications.

Abstract: The invention relates to an electronically scanned antenna comprising an array (11) of elementary sources, an energy-focusing reflector (10), and feed and control electronics; the array (11) is situated in the focal zone of the reflector, while the feed and control electronics includes a plurality of attenuator and phase shifter circuits (24) controlled by a control unit (27), with said circuits having their outputs connected to at least one combiner (28). The invention is particularly suitable for space telecommunications.

Abstract: A method of digitally evaluating the frequency and the phase of signals in the form of digitized samples, the method being wherein it comprises in succession:a stage during which numbers corresponding to the samples of the signal to be analyzed are processed in order to convert them into the form of an analytic signal whose real portion coincides with said signal to be analyzed; and, in parallel therewith:a stage of estimating the parameters to be analyzed which is performed in an overall manner on the basis of estimators and of selection criteria by working on the phase of the signal without using any operator of the Fourier transform type or any hypothesis test either separately or simultaneously; anda stage of estimating the differences between the real signal as taken in this way and the signal obtained from the estimated parameters, thereby making it possible to deliver data in digital form relating to the quality of the analyzed signal and to the reliability of the estimated values.

Abstract: A filter having a dielectric resonator, the filter comprising at least one cylindrical cavity (10) containing a cylindrical dielectric resonator (11) whose axis of symmetry (.DELTA.) is colinear with the axis of said cavity (10), and the resonator being held in a longitudinally asymmetrical position inside said cavity (10) by a mandrel system which clamps around the cylindrical portion thereof and which includes at least one spoke for fixing it to said cavity while leaving play relative to said cavity.

Abstract: A radio-optical transmission system in particular for space telecommunications, comprising a radio-optical interface between a first modulated radio wave (15) and a light wave (18), wherein the transmitted light wave (18) is subjected to wavelength modulation.

Abstract: A signal may be demodulated without using any analog components by using a digital processor. A digitizer delivers the amplitude of the signal to be demodulated at a sampling rate. The signal is acquired from the digitizer and stored in a common memory. The amplitude samples are converted to phase samples. Symbol rate phase hypotheses are generated for splitting the time signal into slices. The carrier phase for one symbol is then calculated for each symbol rate phase hypothesis so that the carrier phase can be estimated over a plurality of (S) symbols. The symbol phase is compared to the carrier phase so that the demodulated signal may be extracted and so that the quality of the demodulation may be estimated.