Abstract: Disclosed is a improvement in the fabrication of a scintillator, notably for the input screen of an X-ray image intensifier tube. According to the disclosure, the substrate on which a layer of scintillating material such as cesium iodide deposited in is made to grow is subjected to a treatment resulting in the formation of an alveolate structure or surface state, the consequence of which is the formation of thinner needles. The reduction of the mean diameter of the needles results in a improvement of the resolution of the device.

Abstract: A coder comprising banks of analysis filters (26, 27) for partitioning the spatio-temporal spectrum of each television image into sub-bands. The banks of analysis filters are coupled to devices for differential coding (30.sub.i, 31.sub.i, 32.sub.i) for separately coding the signals obtained in each sub-band. The decoder comprises prediction loops (24; 25; 12, 17 . . . 20, 3, 21, 22, 23) equal in number to the number of sub-bands for reconstructing each television image transmitted by the coder portion together with its level of resolution in each of the sub-bands.

Abstract: The antenna is produced by placing radiating elements (70) in at least one of the spaces occupied by the various vehicle external lights. The radiating elements can be dipoles formed by metallizing the lens (43) which closes the headlight casing (40) and the casing itself can be used to reflect the electromagnetic energy forwards.

Abstract: A thermal image detector and, more particularly, linear or matrix pyroelectric detectors. These detectors work differentially in successive phases of illumination and masking via a shutter that is synchronized with signal processing circuits. The detector generates differential measurement signals representing variations of pyroelectric signals recorded during a cycle comprising a masking phase and an illumination phase. To eliminate fixed pattern noise, it is proposed to make the measurements by difference between two successive cycles of masking and illumination, the order of the illumination/masking cycles being reversed between the two cycles but the measurements being made identically in both cycles. A memory records the signals during a cycle. A subtractor subtracts the signal of the current cycle from the signal recorded in the previous cycle.

Abstract: Disclosed is device with high linearity for limitation of a characteristic of a signal to a maximum value S.sub.max, and notably the amplitude of a radar signal in a reception system with high linearity. The device comprises a limiter having a limitation threshold S.sub.lim that can be switched over to two possible values S.sub.h and S.sub.b chosen so as to be respectively higher and lower than S.sub.max and means to activate the switching over of the limitation threshold S.sub.lim to either one of the foregoing values, depending on whether a measurement representing a characteristic of the signal such as the amplitude delivered by measurement means is higher or lower than a given comparison threshold V.sub.H. A device such as this is very useful in a radar reception system with high linearity carrying out an analog-digital encoding of the radar signal, for it protects the encoder used from saturation with a minimum lowering of performance characteristics in terms of dynamic range and linearity.

Abstract: Disclosed is a non-linear optical device in which the non-linear medium comprises a circular surface on which the light beam to be processed gets reflected. A structure such as this can be used to resolve the difficulties of making mirrors of the cavity containing the non-linear medium.

Abstract: The disclosure relates to analog-digital converters. It is sought to limit the power consumption and obtain a better compromise among the different performance characteristics of the computer. In a general structure of a converter there are, firstly, a coarse converter for the most significant bits and, secondly, a fine converter for the least significant bits. One of them, generally, the fine converter, has differential amplifiers [AD(1) to AD(N)]receiving the voltage to be converted (Ve) and a reference voltage. It is proposed to place sample-and-hold circuits [EB(1) to EB(N)] at output of these differential amplifiers and to eliminate the sample-and-hold circuit that is often placed upline with respect to these amplifiers.

Abstract: The method relates to the reconfiguration of meshed networks for telecommunications systems with time-division multiplexing, i.e. to a modification of the routing of the signals so that they can be sent with the utmost efficiency despite breaks in the network. In a network comprising nodes distributed in a loop and, possibly, lateral nodes, when breaks cause the loop to be split into sections, the method consists in using standby lines, if any, to connect the lines to one another and to select these standby lines to join the nodes into one network reconfigured by a path without redundancies, i.e. by a path in which the lines are crossed once and only once in each direction. Application to networks for telecommunications systems with time-division multiplexing.

Abstract: The disclosed circuit decouples the aiming of an electronic scanning antenna from the motions of its platform which is assumed to be a moving body. It has two independent tracking channels which determine the direction cosines of the beam along pitch and yaw axes of a referential trihedron that is related to the platform and that has its roll axis colinear with the direction of orientation of the antenna. Each of these channels is decoupled from the motions of the platform by the introduction of a variable that is deduced, by a stabilization circuit, from the gyrometrical measurements of an inertial unit linked to the platform. This device makes it easy for the beam of the antenna to carry out a watch scanning operation or target-tracking operation that is independent of the motions of the platform. Should the electronic scanning antenna form part of a homing unit of the missile, it can easily be complemented by a proportional navigation guidance device.

Abstract: The device according to the invention includes at least one rotational actuator fitted with a return spring and a connecting rod connected to the rotational actuator to transmit a linear movement to a mechanical part. The rotational actuator is moved by a rotational electromagnet whose angular position is controlled by a pulsed, periodic current. The device also includes apparatus for removal of the magnetizing energy stored in the electromagnet.

Abstract: A flip-chip process in which the chip is positioned with its contacts facing a substrate. Small gold balls, obtained by the melting of the end of a gold wire, are soldered to the contacts of the chip and a segment of the gold wire is left attached to the ball. The mounting on the substrate is under heat, for example by means of a heating table, by positioning the chip on the substrate and by making use, for this purpose, of wire segments that are suitably arranged during an intermediate operation which consists of folding them in a predetermined way. A solder paste, deposited beforehand by means of a stencil, provides for the soldering between the balls and the facing parts of the conductors of the substrate.

Abstract: The invention is a mechanical sensor produced from a polymer film whose upper part (A) is made conductive, the lower part (B) remaining an insulator. When a strain is applied, the mechanical sensor according to the invention distorts, varying the resistance of part (A) and thus allowing the strain to be measured. Preferably, the polymer used is a thermostable polymer.

Abstract: To harden transmissions, in both directions, between a master station (1) and a slave station (2), a table of communication parameter values is memorized in each station and the table values are then used in accordance with the master station's decision. Each message from one station to the other contains information to allow the receiving station to determine the parameter values to be selected in the table to eliminate values where there is a high risk of jamming.

Abstract: A method for the defruiting of the responses from radar transponders received by a secondary radar in response to interrogations sent by the radar recurrently, a recurrence being formed by the interrogation and the responses received during a listening period that follows the interrogation, the defruiting operation consisting in verifying that a response received at an instant T of the recurrence is correlated by the presence of at least r-1 other responses received at the same instant T of their recurrence, these responses forming part of a sequence of at least r recurrences including the current recurrence, the method being one wherein the correlation is achieved over several chosen sequences and wherein the correlation is declared to be positive if it is positive for one of the sequences.

Abstract: The invention is a resonant tunnel effect quantum well transistor. To improve the gain by avoiding the storage of charges in the well, which consists of layer (14) with a narrow forbidden band and two barriers (13, 15) with a wide forbidden band, the quantum well is laterally bounded--in the plane of the layers--by a depleted region (22) which forms a quantum box whose dimensions are smaller than the De Broglie wavelength. Application to fast electronics (200 GHz).

Abstract: An acoustic transducer of the flexural strain gauge type, in which a shell body of oblong section is stressed by a motor along a major axis of this section. A viscoelastic element absorbs the slow deformation of the shell under the effect of submersion. The viscoelastic element exhibits a considerable stiffness at the frequencies of use of the transducer so as to transmit the vibrations from the motor to the shell with adequate efficiency. Such a device makes it possible to manufacture a flexural stain gauge transducer capable of withstanding considerable submersion without the motor fracturing and the efficiency of which is greater than 75%.

Abstract: The invention pertains to an electromagnetic wave modulator comprising a quantum well semiconductor structure having two adjacent wells, the coupling of which is modified under the effect of an electrical field by the use of the phenomenon of anti-crossing of resonating levels. With this type of modulator, it is possible to attain 20% of modulation (as in the prior art) but with heightened sensitivity to the electrical field and a very short response time.

Abstract: The disclosure relates to thermal image detectors and, more particularly, to linear or matrix type pyroelectic detectors. These detectors work differentially, in successive phases of masking and illumination, by use of a shutter that is synchronized with the signal processing circuits. The detected signals are shed in the form of charge packets into a shift register (RD). To reduce the noises that are proportional to the duration of the illumination or masking phases, the shutter is made to work at higher speed and several successive illumination/masking cycles are carried out by making the shift register go backward between two cycles. The shift register is emptied to give an image signal only after two or more cycles.

Abstract: The method according to the invention consists of a first step in which messages sent by the sending subscriber are segmented into cells, a second step in which initial processing is carried out on each cell in order to space them uniformly at a minimum time interval at least equal to a determined resolution time, a third step in which a second processing succeeding the initial processing is carried out in order to space groups of cells with the same throughput by a minimum time interval determined as a function of the throughput allocated to each network subscriber, and a fourth step in which cells thus spaced are transmitted in a determined virtual circuit on the network.

Abstract: In an electrochemical sensor, a gas analyzing electrochemical cell is implanted directly on a substrate wafer. The entire wafer is coated with enamel layers except at the places needed for the electrical connections. A fixing part fixes the sensor in a housing in such a way that the electrochemical cell is inside the housing which contains the gas to be analyzed. This fixing part provides imperviousness and prevents the gases from reaching the electrical connections.