Abstract: An antenna of the type comprising a set of distributor circuits made by symmetrical strip line circuit technology, distributing microwave energy to M radiating elements. The symmetrical strip line distribution circuits are placed so that they have at least one portion of their ground planes in common, thus reducing the bulk and weight of the antenna.

Abstract: A simulator comprises a dome on which are formed synthesized large-field images, the image-forming surface of the dome being "active", i.e., it is not used as a projection screen, but the images are formed directly by "cells". As a result of this arrangement, successive portions of the spherical surface, which are dark in the absence of excitation, make it possible to increase the contrast of the images obtained. According to one embodiment, these cells comprise encapsulated liquid crystals.

Abstract: A device for the generation of several light beams is used notably to illuminate light spatial modulation screens with the 16/9 format in color image projectors. The aim is to improve the luminous efficiency. The disclosed generator device has a light source producing a primary beam and two wavelength selective mirrors. The two selective mirrors are illuminated by the primary beam and produce two secondary beams of different wavelengths. On the one hand, the two selective mirrors are placed side by side and intercept different parts of the section of the primary beam. On the other hand, a rear face that is at least partially reflective is positioned opposite the source with respect to the selective mirrors.

Abstract: The system provides for a function of smoothing, and therefore, softening the contours without any loss in addressability, as well as for the homogenization of the spatial distribution in the screen. It has a microprocessor based management and control circuit, an image generator, an image memory, a scanning circuit in X and Y directions and a video processing set placed between the memory and the matrix screen display device. The management and processing circuits are determined so that the matric scan is done by taking into account, for each image point to be displayed, data stored in a zone of the image called a micro-region, formed by at least three pixels in X and at least three pixels in Y, the micro-region being centered on the coordinates of the image point to be displayed.

Abstract: The disclosed deflector includes a thin film of liquid crystal on either side of which there is positioned at least one plane of electrodes, the assembly forming an array of elementary, quadripolar phase-shifters placed side by side, their electrodes being taken to different control potentials, generating a spatial modulation of the phase of the beam going through the deflector.

Abstract: The present invention provides phased arrays using monolithic technology of diffusions over whole wafers for working in millimetric wave frequency bands. The reflector array includes a plurality of metallizations connected together by diodes whose capacity can be varied. Thus direct control of reactive impedances is obtained. With the metallized strips placed at a distance substantially equal to .lambda./4 from a ground plane, it is possible to control locally the phase of the reflected signal.

Abstract: The antenna has a support with a metallic structure and cables. In order to give the antenna good resistance to wind, it is made by means of rigid half-wave dipoles and these dipoles are mounted directly on the mechanical structure.

Abstract: Disclosed is a source of microwave radiation, namely a source enabling the absorption of multiple reflections for the illuminating of a lens in order to form an electronic sweeping antenna. The source includes a layered arrangement of elementary illuminators in a direction substantially parallel to the electrical field of the microwave energy transmitted. In one embodiment, each elementary illuminator has the following successively, in the direction of propagation of the energy: a plane forming a short circuit; a plane forming an incidence filter, parallel to the above plane, located at a distance from the above plane of the order of half of a wavelength, including two tracks parallel to each other and perpendicular to the electrical field between which resistive elements are connected; and, a plane bearing a rdiating element of the snake line type, extending in a direction substantially normal to the electrical field.

Abstract: A low-frequency hydrophone for a sonar array comprises at least a lacunary ceramics element with open porosity saturated by a viscous fluid, on which metal electrodes have been deposited. This hydrophone forms a high-pass filter whose cutoff frequency is adjusted by modulating the area of the electrodes. The present invention may find particular application in towed linear arrays and passive sonars.

Abstract: The invention is a process to manufacture a controlled-porosity ceramic material by synthesizing an aerogel produced by hypercritical drying of a high-porosity gel.Applications in the submarine acoustic field (active and passive sonars).

Abstract: Disclosed is a method for the mounting, on an flexible substrate, of miniature electronic components of the beam lead type. Said method consists, after a first connection lead of a component has been soldered to the substrate, in arching each of the other connection leads of the component considered during their soldering by pressing the connection lead considered on a metallized zone of the substrate by means of a tip of a soldering tool while, at the same time, making a approaching movement towards the body of the component considered with this tip before carrying out the soldering operation itself. Through this mounting method, the beam lead electronic components are no longer placed flat against the substrate with their connection leads in an extended position but are arched on these leads. This gives them a freedom of play that enables them to absorb mechanical stresses by adopting positions of greater flatness or lesser flatness on the substrate.

Abstract: A method for the manufacturing, by epitaxy, of monocrystalline layers of materials with different lattice parameters that includes:a first step for the epitaxial deposition, on a first layer made of a material having a determined lattice parameter, of a second layer with a determined thickness made of a material having a lattice parameter different from that of the first layer,a second step of ion implanation designed to create a zone, in the second layer, limiting the spread of the dislocations, and at least,one third step for the epitaxial deposition, on the second layer, of a third layer made of the same material as the second layer. The disclosed method can be applied to the manufacture of opto-electronic or microwave devices made of GaAs on Si substrates.

Abstract: Disclosed is a sonar for avoiding sub-surface underwater objects, for a surface vessel, having its directivity in elevation optimized to observe the surface and its surface reverberation reduced to the minimum. It consists in using an acoustic antenna having two columns of n transducers, the first column insonifying, at transmission, an elevation sector corresponding to the collision-risk zone and forming channels at reception, in the insonified elevation sector, the width of the channels being all the finer as the desired precision of the measurement of the position in elevation is high. The second column is necessary for the localization in relative bearing. The disclosure can be applied to the precise localization in elevation of objects located in the path of a vessel.

Abstract: The present invention relates to a method and apparatus of encoding and decoding blocks of data words. Each block has a fixed number of data words with a maximum of nbits, and a position of a data word within a block is diagonally identified by a series of absolute addresses having consecutive values. In the encoding of the data words of a block, the data words are classified into groups based on their most significant non-zero bit. Then the corresponding absolute address of each classified data word is encoded based on the absolute address of a previously encoded data word in the same class as the current classified data word and the number of data words encoded in classes less than the current classified data word since the previous encoding of a data word in the class of the current classified data word. Each data word with its ith and greater bits omitted is then transmitted along with the encoded absolute address.

Abstract: This combined microwave and optic rotary joint has a fixed part and a rotating part in rotation about an axis .DELTA. in relation to the fixed part. It has at least one pair of microwave guide inputs, one of which is positioned in the fixed part while the other is positioned in the rotating part, these microwave guide inputs being coupled to each other by a coaxial link that is fixedly joined to the rotating part and placed in a conduit going through the fixed and rotating parts along the rotation axis .DELTA.. The core of the coaxial link is drilled with a longitudinal channel enabling the passage of an optic fiber fixedly joined to the rotating part. The end of this optic fiber goes through the fixed part and emerges in a case where it is coupled through an optic rotation plane to the end of another optic fiber fixedly joined to the fixed part.

Abstract: Synchronization for a device receiving an input sequence of variable length rasters even in the presence of transmission errors. Each variable length raster is preceded by an N times identically repeated prefix, this prefix is composed of a fixed binary pattern separator and a parameter word describing the variable length raster to follow. Upon identifying a fixed binary pattern separator, even in the presence of transmission errors, the synchronization device outputs asynchronization signal signaling that a parameter word is to follow. The parameter word input is then subjected to transmission error elimination and output to the receiving device. Thus the receiving device is able to properly input the incoming variable length raster based on a accurate parameter word.

Abstract: The present invention concerns a transistor of semiconductor materials of the 3-5 group on silicon of the type comprising a silicon substrate, at least one layer of semi-insulating 3-5 material and several doped layers of 3-5 group semiconductor material in which is defined at least one conducting channel equipped with a gate metallization, each channel being situated between two access regions alternately known as source and drain, each source and drain regions with a metallization, one of the two access regions to a channel being electrically and thermally connected to the silicon substrate. In accordance with the invention, the transistor comprises between the silicon substrate and the semi-insulating layer of 3-5 group semiconductor material, at least one buffer layer of intrinsic silicon.

Abstract: In a simulator for helicopters, the images seen are displayed through the bottom windows by means of a system collimated to infinity, including, for each side of the cockpit, a projector (15, 16), a spherical mirror (12, 13) and a screen (17, 18).

Abstract: The disclosure relates to the making of lasers. It is sought to obtain a laser that emits at only one frequency without using frequency selection means (such as filters, etc.) needed in certain types of spectral wideband lasers (vibronic type lasers for example). It is also sought to make the laser tunable by simple means. To achieve these goals, it is proposed to define a laser cavity in which one of the mirrors is not a standard mirror but a mirror with an active function in the sense that it does not merely reflect light but itself produces light at only one wavelength. The active mirror is preferably a Bragg reflector made with an alternation of layers, at least one of which is a semiconductor layer. This layer collects electron-hole pairs in response to the excitation by the fluorescence photons. It re-emits photons at a wavelength determined by the forbidden band width of the semiconductor.

Abstract: In a reflective angle of a radar, auxiliary elementary sources are positioned beneath the main source. By the division of the measurement signals of the measurement channel of the main source and of the auxiliary measurement channel, a monotonous characteristic is obtained, enabling the elevation angle to be measured with high precision. FIG. 1.