Abstract: A process of acoustic emission for sonar with a separate emission array from the receiving array. The emission array has the shape of a linear acoustic array and can either be towed simultaneously with linear acoustic receiving array or be suspended from a helicopter to form a "dipping" type sonar. Detection using this type of sonar is facilitated by increasing the sound level via the directivity index, while reducing the level of reverberation originating from the bed and from the surface of the sea.

Abstract: Disclosed is a dc/ac inverter for the supply of alternating current to the windings of a synchronous electrical motor, especially for the traction of an electrical vehicle. During each half-wave of the alternating current, the dc/ac inverter with solid-state switches delivers steady levels of constant intensity. During each steady level, the intensity of the current is determined by the cyclical ratio of a chopping signal that controls the conduction of the transistor-based or thyristor-based switches. At zero speed of the rotor, the frequency f of the chopping signal has a value (f', 1 khz) smaller than the chopping frequency (8 kHz) for a speed different from zero. Thus the starting losses or the losses with the rotor off are minimized.

Abstract: The disclosure relates to the transmission of data by packets, in a network, with a search for an optimum use of the allocated band of frequencies. The packets are all formed by a header followed by an information field. The headers are all sent out on the same carrier frequency and the radio resources allocated to an information field are limited to a parallelogram demarcated by two first parallels corresponding to two fixed frequencies external to the frequencies allocated to headers and by two second parallels that have the same frequency/time slope for all the packets and whose position in time is deduced from the observation of the header. Thus, with knowledge of the resources used by the packets that are being transmitted, a terminal may send out a new packet as closely as possible to the packets that are being transmitted, but without any risk of interference with these packets. Application to transmission by packets.

Abstract: This monostatic LIDAR system is a pulsed-radiation LIDAR system comprising, for the separation of the laser emitter beam from the laser echo backscattered by the photodetector of the receiver, an optical separator that deflects an incident light beam in different directions, depending on whether it transmits or reflects this beam, the coefficient of transmission or the coefficient of reflection of this optical separator varying as a function of the energy density of said incident light beam. Advantageously, this optical separator is constituted by a layer of vanadium dioxide VO.sub.2 deposited on a transparent plate. An optical separator of this kind is used to obtain a total transmission/reception output greater than that of an optical separator with semi-reflective plate while, at the same time, preserving the advantages that an optical separator of this kind brings about in the optical architecture of a LIDAR, these advantages being simplicity, easy setting, compactness and low-level parasitic reflections.

Abstract: A method and device for interconnecting stacked semiconducting plates, in which each of the plates has an integrated circuit. The semiconducting plates (P) are stacked and made solid with each other. In one embodiment, their connecting contacts are connected by a wire (F) to any one of the faces of the stack except one (B), which is to be in contact with a printed circuit. Connections of the plates together and with the printed circuit is made on the faces (F.sub.V, F.sub.S, F.sub.L) of the stack.

Abstract: An adaptive method for television image encoding by splitting the video image to be transmitted into sub-bands at the time of analysis filtering of the image encoder. These sub-bands are split into a tree-like structure by filtering and decimation. Local adaptive filtering is carried out in the analysis filters of each sub-band.

Abstract: The invention consists, after launching (1) a vehicle (9), in guiding (2) the vehicle (9) towards the mine (5; 6) by means of a sonar coupled to a tactical control station (12) of a hunter (8), fulfilling the functions of classification and permanent monitoring of the position of the vehicle (9) relative to the mine (5; 6), in releasing a locating means (13), carried by the vehicle (9), once the vehicle (9) has arrived at a determined distance from the mine (5; 6), making it possible to fulfil a target designation function by interacting with the vehicle (9) and the tactical control station (12) of the hunter (8), then in communicating (3) to the vehicle (9), by means of the tactical control station (12), the navigation parameters necessary for its attack strategy as a function of the type of mines (5; 6) encountered, and its position referenced by the fixed locating means (13), and in destroying (4) the mine (5; 6) according to the attack strategy acquired by the vehicle (9).

Abstract: Disclosed is a method for the manufacture of film made of polymer based material that is particularly well suited to open-pore type cross-linked polymers. The disclosed method comprises the following steps: the making of a cell C comprising, between a substrate S.sub.1 and a substrate S.sub.2, a compound comprising a precursor of the polymer P, at least one of the substrates S.sub.1 and/or S.sub.2 being soluble in a solvent .SIGMA..sub.1 and/or a solvent .SIGMA..sub.2, said solvent .SIGMA..sub.1 and/or said solvent .SIGMA..sub.2 being a non-solvent for the polymer P; the polymerization of the polymer P within the cell C; the immersion of the cell C in the solvent .SIGMA..sub.1 and/or the solvent .SIGMA..sub.2 so as to eliminate the substrate S.sub.1 and/or the substrate S.sub.2. Applications: liquid crystal devices, molecular sensors.

Abstract: This system for receiving or reading digital serial information provides for the information to be sampled at regular intervals under the control of a local clock. It includes a table containing for each pair of values of consecutive information samples a measured phase value.

Abstract: Disclosed is an optical amplification device comprising an amplifier medium inserted between two mirrors and an optical pumping source. The mirrors are confocal mirrors whose focal plane is located in the vicinity of the center of the non-linear medium. This medium has a match-stick shape with a large axis in one direction forming an angle alpha/2 with the optical axis of the cavity defined by the two mirrors and the amplifier medium. This architecture enables an incident optical wave to pass several times within the amplification device leading to an increase in the performance characteristics of said device.

Abstract: The invention relates to a biochemical sensor including a substrate on which yeast cells are deposited which are capable of capturing one type of molecules (M) and of producing a chemical entity (P) at the outcome of the capture; it also includes means for detecting the entity (P). The yeast cells employed are yeast cells obtained by genetic manipulation, in which the capture sites have been adapted to the type of molecules (M).

Abstract: The invention relates to a modulation ratio amplification device, particularly for amplification at UHF. This device comprises means for making two optical waves, which are of the same amplitude but offset in frequency, interfere. These means may be a frequency converter, coupled to a continuous phase shifter; they may also involve two phase shifters: one continuous, the other varying sinusoidally over time. This type of device makes it possible greatly to amplify the desired modulation ratio, using an optical amplifier, given that the continuous background of the optical signal is suppressed.

Abstract: Disclosed is a thermionic cathode for electron tubes comprising a material that has a substrate, a compound of an element forming an emitting monolayer, chosen from among the rare earth zirconates, rare earth hafnates, rare earth aluminates and rare earth berylates, and a reducing agent which, at the working temperature of the cathode, reacts with the compound releasing the element that forms the monolayer. Application in particular to electron grid tubes. FIG. 1.

Abstract: This invention concerns a missile launching system, and particularly a missile launching and orientation system. It can be used to modernize missiles with an inclined launch at an angle by transforming them into missiles controlled for circular defense, avoids ejection of the passive mass within the launching area. In order to do this, the launching system comprises launching means, aerodynamic control surfaces with drive and means of orientation including at least one gas generator and nozzles connected to it. Orientation means are located in an annular body rigidly connected to the rear part of the missile body. The outside surface of the annular body is cone-shaped and is covered with a thermal insulating material forming a gas pipe, the profile of which is a continuation of the profile of the nozzle of the missile cruise engine.

Abstract: A vocal synthesis method in which a speech signal is reconstituted by the selection from a dictionary of waveforms for the excitation of long-term and short-term predictive filters. To preserve, in the synthetic speech messages read at low speed or high speed, the same pitch and the same spectral characteristics as the messages read at normal speed, the period of excitation of the long-term predictive filter and the ranges of computation of both predictive filters are modified as a function of the speed of synthesis without modifying the values of pitch applied to the long-term predictor. Such a method may find application to dictaphones, telephone answering machines and vocal message systems.

Abstract: A rear feed source for a reflector antenna and an antenna using such a source. The source includes at least one horn connected to a waveguide. The horn has at least two inclined walls forming an aperture, each wall being extended by a wall with a different inclination. This invention can be applied to radars, notably surveillance radars.

Abstract: A device for linearly extending the duration of laser light pulses by subjecting the pulses to double diffraction based on a series of variable step gratings placed at right angles to each other. Increased power density is obtained by placing a compression grating at an angle such that each wavelength of light emerging from the compression grating travels an optical path of approximately the same distance, and focusing the emerging light with a lens. Increased amplification is obtained by placing a segmented laser amplifier, one segment aligned with each wavelength of light separated by the double diffraction of the series of variable step gratings and interposed between the series of variable step gratings and the compression grating.

Abstract: A thermal imaging detector including a layer of heat-sensitive material which includes a doped ferroelectric material exhibiting a pronounced rise in resistance with temperature in the vicinity of the ferroelectric/paraelectric transition, a multiplexing circuit, a thermally insulating thin-film microstructure, and a matrix segmentation at the level of the material of the heat-sensitive layer, so as to define heat-sensitive picture elements.

Abstract: An optoelectronic quantum well device comprises a stack of layers that have different gap widths and constitute quantum wells possessing, in the conduction band, at least two permitted energy levels, this stack of layers being included between two reflection means. The device also comprises a diffraction grating between one of the mirrors and the stack of layers.

Abstract: The disclosure relates to the transmission of data by packets on carrier frequencies with spreading and de-spreading of the data elements. In order to reduce the risks of overlapping among packets sent out by different transmitters, each packet to be transmitted is designed according to the characteristics of frequency spreading and/or code spreading of a common standard packet, constituted by successive segments all orthogonal to one another, the first segment comprising a header designed for identification. At reception the header, when it is found, activates the processing of the corresponding packet with de-spreading as a function of the characteristics of the spreading of the standard packet as they are known to the transmitter.