Abstract: Disclosed are a method and a device to detect the intermingling, hence the garbling, of pulses received by a secondary radar by phase analysis. The monopulse reception antenna of a secondary radar delivering a sum signal given by its sum channel and a difference signal given by its difference channel, the method according to the invention consists in analyzing the phase difference between the sum signal and the difference signal, the garbling of at least two received pulses being detected by a phase difference with a value that is substantially different from 0.degree. or 180.degree.. Application to the detection of garbled pulses received when the working frequencies of the transponders are very close to one another.

Abstract: The integrated circuit chips (5) are mounted on a ferrite support (20). The ferrite support is metallized uniformly (26) on its lower face and bears metallization zones (21, 24) on its other face. To certain of these zones (24) serving as a ground plane, there are attached the integrated circuit chips (5). The other zones (21) act as relays to connect the supply voltages that are applied by means of a linking wire (7') and a thin film decoupling capacitor (10, 11, 12) borne by the chip. The ground zones (24) are connected to the general ground plane (26) by metallized holes (25). The linking wire (7') is positioned so as to face a bared part of the ferrite to prevent any parasitic resonance.

Abstract: Method and device for real-time separation of signals received by a predetermined number of sensors, the mixture being linear. The signals received are firstly decorrelated [s(t)], and they are then introduced into a rotator which calculates, through a succession of elementary rotations [Q.sup.(1), Q.sup.(2), . . . Q.sup.(m) ], the orthogonal matrix (Q) making it possible to recover the independent source-signals [x(t)] by multiplication (F) of this matrix (Q) by the decorrelated input signals [s(t)]. The identification of (Q) is based on the estimation of statistical magnitudes called "cumulants".

Abstract: A method of growth according to which a layer of a material having apertures is made on the surface of a substrate. A material is deposited in each aperture. When this material is liquid, it can absorb the material to be grown. Then, the growth is done in vapor phase. The material of the layer is chosen in such a way that there is neither growth nor nucleation on its surface during the growth in vapor phase. The disclosed method can be applied to the making of crystal whiskers positioned with precision, and to the making of tip type microcathodes.

Abstract: The invention is a series of amorphous copolymers which, used in association with a small molecule, provide photorefractive materials that can be used in optical signal processing. These copolymers contain an active non-linear optical group and a group which contributes to their photoconductivity. ##STR1## where: X is H, CH.sub.3, Cl or FY is H, CH.sub.3, Cl or F2.ltoreq.n.ltoreq.42.ltoreq.m.ltoreq.4The electron-donor group D being: --O--, --S--, ##STR2## or --COO-- The electron-accepter group A.sub.e being: --CN, --NO.sub.

Abstract: The disclosed method consists of: the cutting up, after sampling, of the speech signal into frames of a determined duration; the carrying out a first self-adaptive filtering of the sampled signal (Sn) obtained in each frame to limit the influence of the first formant; the carrying out a second filtering to keep only a minimum of harmonics of the fundamental frequency; and the comparing of the signal obtained with two adaptive thresholds SfMin(n) and SfMax(n), respectively positive and negative and changing as a function of time according to a predetermined relationship so as to choose only the signal portions that are respectively above or below the two thresholds.

Abstract: An optoelectronic detector using a photodetector (1) and a stress induction device for inducing elastic waves with the stress inducing device being mechanically coupled to the photodetector. The stress inducing device includes an excitation which permits the transmission of the elastic waves.

Abstract: A method for the compression of images comprises two steps. A first step of vector quantization compresses a source image into an image of indices that is coherent in relation to the source image. A second step again compresses this image of the indices according to a prediction method using a network of multilayer neurons. Application: compression of images for their storage and transmission.

Abstract: The present invention relates to a method of realigning the local oscillators of a receiver, as well as a device for implementing the method. In a receiver with a high frequency/intermediate frequency translation oscillator, an intermediate frequency/baseband translation oscillator, and a sampling oscillator receiving a signal modulated by at least one circuit for inverse fast Fourier transform FFT.sup.-1 computation according to a multicarrier modulation of OFDM (Orthogonal Frequency Division Multiplexing) type with addition of a transition interval at the start of each transmission interval. The spectrum of the signal has two master lines with a fixed frequency difference between them.

Abstract: A sensor of weak magnetic fields with magnetoresistive effect features a metallic multilayer formed by alternating magnetic and non-magnetic metals. In order to detect weak fields, a sensor is described wherein a magnetic field is coupled by an anti-ferromagnetic type coupling with a first neighboring magnetic layer and by a ferromagnetic type coupling with a third neighboring magnetic layer, so that there is frustration of coupling. The first and third magnetic layers are blocked by their strong coercive field. The sensor finds particular application to detection on magnetic media.

Abstract: An identification system is disclosed which includes marks on an object for locating a region of the object which contains an identification in the form of either an etching or a responsive electronic circuit and a detection device for detecting the proximity of the first mark in order to localize the position of the etching or responsive electronic circuit so that the etching or responsive electronic circuit may be read.

Abstract: A light intensity modulator with a predefined range of modulation wavelengths (preferably a narrow range) can be adjusted by a control signal. This modulator receives a light beam and retransmits a modulated light beam in which any wavelength within the modulation range is modulated. A light intensity detector receives this modulated beam and outputs an electrical signal which is a function of the luminous intensity detected. Such a device finds particular application as a spectrophotometer.

Abstract: A transmission method and a transmitter and receiver Structure is disclosed which provides for transmission of modulated waves using long pulses with a plurality of frequencies. The method involves two consecutive frequencies being separated by 1/T, where T is the period of the useful transmission intervals. The method and the apparatus are particularly suited to broadcasting and reception of television and radio signals as well as telephone communications between exchanges and between radio telephones and communication stations including terrestrial stations and satellites and local computer networks. Most particularly the method is applicable to high fidelity radio transmissions as well as to high definition television (HDTV).

Abstract: A semi-conducting structure delimits two quantal wells (CP1, CP2) connected across a barrier layer (CB). The application of an electric field to the structure makes possible the transfer of electrons from one of the wells to the other. The electron-hole pairs are created by a wave-pump, or by the doping of one of the wells. This makes possible, in particular, a dual control by means of the wave-pump and the electric field, thus creating an "AND"-function modulator.

Abstract: The invention is a hollow fiber with, over the full length of the fiber and between each fiber channel (3, 4) and the core, at least one stress zone (5, 6) to create an anisotropic stress distribution which subjects the fiber core to a tensile stress. The cable design is advantageous in that it is possible to control the sign of the fiber intrinsic birefringence. The cable is thus advantageous for use as a pressure sensor or pressure transducer.

Abstract: A structure which includes a composite material formed of a plurality sheets forming plies. A casing is formed between two of the plurality of sheets forming the composite material, the casing having an internal diameter. Further, an optical fiber is located within the casing and has an external diameter which is less than the internal diameter of the casing, the optical fiber also having a slow axis and a fast axis of propagation.

Abstract: A high-sensity infrared detector system includes circuitry for summing the luminance values of flux received by the photosensitive cells in a detection matrix, these values being read in succession by a CCD read circuit at a frame rate and then converted to select adding operations applied to match the characteristics of a detector scan. An accumulator consists of an integrator having a multiplier connected to a memory containing sets of coefficients, each coefficient having two possible values and each value indicating a type of addition--with or without a cell shift. Secondly, an accumulator is provided to sum the luminance values following a defined scheme. A scanning system outputs data concerning the scan characteristics to detector selection circuits to select a set of coefficients from memory.

Abstract: A method which constructs, in each transmitter/receiver of a mobile body or vehicle, information tables recording the changes undergone by a radio channel by memorizing, during consecutive time intervals of a determined duration dT that are smaller than the period of recurrence T, of the statuses of the radio channel, namely "in collision", "busy" or "free". The method then sets fixed transmission instants in each transmitter/receiver, these fixed transmission instants being temporally spaced out at intervals equal to the recurrence period T, to predict the status of the channel for each fixed transmission instant as a function of the status of the channel memorized at the instant preceding it with a temporal shift equal to the period T, and in deciding to transmit at this instant if the predicted status of the channel is not a status of collision or to transmit at an instant deferred with respect to the predicted instant if the opposite is the case.

Abstract: A low loss microwave surface acoustic wave filter, comprising input (2, 3) and output (4, 5) transducers, acoustically associated with coupling transducers (6, 7).The relative positions of the transducers 2 to 7) and of their O reflectors are chosen, having regard to the weightings of the coupling transducers (6, 7) in order to obtain the desired transfer function for this filter.

Abstract: A tunable high-frequency device using a superconductive thin layer with a thickness smaller than the thickness of penetration of a magnetic field is positioned on a dielectric layer. Also included is a means for varying the density of the Cooper pairs of the superconductive thin layer.