Thomson-Csf

Gerard Auvray

Luigi d'Auria

Bernard Desormiere

Yvon Fouche

Philippe Elleaume

Guy Desodt

Hubert Joncour

Jean C Guillerot

Daniel Balduzzi

Jean Anastassiades

A device and a method for the transmission or storage of data optimizing the use of the pass-band. Also, a method for transmission by phase modulation. In order to obtain high data throughput rates, the synchronization of a transmission clock with the reception clocks is used. This synchronization is gotten, for example, by transmission of a pseudo-random code and by the convolution or correlation of the received signals with the pseudo-random code. The invention also enables the elimination of multiple echoes by computation. The invention can be applied chiefly to the transmission of radio programs, television broadcasts or digital data.

Device and method for the data transmission or storage optimizing the

This radar receiver, in particular for a radar having an antenna with beam forming through computation, comprises essentially means for matched filtering having a bandwidth B, means for amplitude and phase detection, and means for analog-to-digital conversion, and is such that said means for analog-to-digital conversion work on the intermediate-frequency signals, at a frequency much higher than said intermediate frequency. The receiver can be fully constructed in gallium arsenide technology.

Radar receiver for a radar having a digital beam forming antenna

A digital filter having parallel paths with a plurality of transverse filters in the paths. The period of treating the digital information of N connections at the output of a circuit for calculating the discrete Fourier transform on 2N points. The output of the transverse filter is fed to a circuit for calculating the inverse Fourier transform. These two circuits permit the transverse filters to function in each path with a data period of N. The filter will find particular application in convolvers, courolaters, and for circuits for the compression of digital pulses. The filter lends itself to application, particularly in radar, sonar, telecommunications, and in sound and imaging systems.

Digital filter using fourier transformation

A method and a device for reducing the power of jamming signals received by the secondary lobes of the main antenna AP of a radar transmitting at a random frequency f.sub.E (n), with which is associated a number of secondary antennas ASl, . . . ASN. The signals used for the calculation in circuit (10) of the weighting coefficients (Wl to WN) to be applied to obtain a signal resulting from the weighted linear combination of the secondary signals Dl, . . . DN to be subtracted from the signal Do in the main channel (VPD) relative to the transmission frequency f.sub.E (N+1) are those (V.sub.0, V.sub.1, . . . V.sub.N) processed in the main and secondary auxiliary channels (VPA, AsAl, . . . ASAN) relative to the transmission frequency f.sub.E (n+1) of the next recurrence train during the period of radar reception of the recurrence train corresponding to the transmission frequency f.sub.E (n) for the jammed range slots selected by circuit (15).

Method and a device for reducing the power of jamming signals received

An apparatus and method for reducing the power of active jamming signals received by the sidelobes of a radar antenna. A known method includes providing a radar with a main antenna and N auxiliary antennas, each antenna being associated with a corresponding processing channel. The signals received by the N antennas are each given a weighting coefficient corresponding to jamming on that channel. The N signals are then combined to form a weighted linear combination which is subtracted from the main channel signal to provide a signal with reduced jamming. The present invention provides apparatus and method for reducing clutter signals (such as fixed echoes and thermal noise) from each of the signals received in the N channels, thus producing very accurate weighting coefficients thereby allowing jamming power to be further reduced. Apparatus and method are provided for carrying out moving target indication (MTI) on all channels, determining the jammed range cells by comparing the main channel signal with the auxiliary channel signals and validating these signals with respect to thermal noise, determining the weighting coefficients from information derived from a given number of jammed range cells (preferably those grouped together at the end of recurrence), forming the weighted linear combination from only those signals which are, in fact, jammed, and subtracting the weighted linear combination from the main channel signal.

Method and device for reducing the power of jamming signals received by

A system for connection by means of optical fibers for the bidirectional exchange of data between a fixed central unit and peripheral units integral with a frame driven with a rotary movement, this system comprising radiating energy emitting and receiving means situated in the fixed part, coupled by optical fibers forming unidirectional data exchange paths to a single mixing fiber, itself coupled to optical fibers forming bidirectional data exchange paths coupled to radiating energy emitting and detecting means associated with the peripheral units integral with the mobile frame. Furthermore, the mixing fiber is split into two parts coupled together by a rotary optical joint.

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Longpont Sur Orge, France

Gerard Auvray