Abstract: The disclosure relates to methods and devices for the real-time localization of terrestrial transmitters belonging to a TDMA type cellular radiocommunications network. The device comprises an antenna array, a multichannel receiver and a digital processor. The method consists of the interception, from an aircraft, of radioelectric signal and the detection of these signal by the implementation of a multichannel synchronization to determine the various sources of transmission, the simultaneous computation of an elevation angle &Dgr; and an azimuth angle &thgr; to instantaneously determine the direction of arrival of the radioelectric signal from the determined transmission sources and the building of track in the geographical areas in which the transmission sources are located in order to estimate the position of the transmitters.

Abstract: A process for the automatic searching by an aircraft for a communication address of a ground entity of an ATN network. In the process, each address is coded according to a hierarchical binary tree structure including several fields. A first field identifies the network and the subsequent fields identify entities of the network. The process determines in the aircraft the address of the communication center to be contacted from the identity of an ground router which it receives, by comparing the received address of the router with those of the addresses contained in a database of the aircraft, and retaining as an address that which has the largest number of characters in common with the address of the ground router, given the tree structure of the addresses. Such a process may find particular application to ATN communications.

Abstract: A system for acquisition of logic states including sensors operable in all-or-nothing mode, each sensor including a switch linked with a pulling resistor between ground and power-supply potential, an analog multiplexer including an output and inputs linking the switches and resistors, voltage representative of the potential linked to a specific input, an analog-digital converter linked to the output, a calculating logic unit which drives the multiplexer and converter, generates input addresses of the multiplexer periodically and sequentially, reads and stores digital values at an output of the converter for each address, determines a digital value of the voltage, determines for each address corresponding to a sensor, a position of the digital value for an address with respect to a threshold, relating to an address, the position representing logic state of each sensor, and an altering device for altering the threshold as a function of the digital value of the voltage.

Abstract: A device for inserting, extracting, and locking a module into, from, and in a rack. The device includes two arms which can pivot with respect to the module and which are articulated together by a common articulation, each of them including, on the one hand, at one end, an anchor for anchoring it into the rack and, on the other hand, a non-common articulation with the module. A device immobilizes one of the arms with respect to the other when the arms are anchored in the rack. Further, associated with at least one of the arms, an elastic device works in compression between the module and the arm when its end is anchored into the rack. Such a device may find particular application in electronics modules for avionics.

Abstract: An antivibration elastic suspension in which a chassis of an inertial measurement unit is placed inside a casing. The inertial measurement unit includes a gyro assembly that is fixed to the chassis by two support rings flexible in terms of torsion and rotation around a fixed axis of the chassis. At least one flexible annular diaphragm is coaxial with the fixed axis and the flexible annular diaphragm is fixed by an interior periphery to an exterior periphery of the chassis and by an exterior periphery to an interior wall of the casing. The flexible annular diaphragm respects a symmetry of revolution exhibited by the gyro assembly with respect to the fixed axis.

Abstract: A method for encoding speech at a low bit rate. The method assembles parameters on N consecutive frames to form a super-frame. A vector quantization of transition frequencies of a voicing during each super-frame is made. Only the most frequent configurations are transmitted without deterioration and the least frequent configurations are replaced by the configuration that is the nearest in terms of absolute error among most frequent configurations. The pitch is encoded in carrying out a scalar quantization of only one value of the pitch for each super-frame. The energy is encoded in selecting only a reduced number of values in assembling these values in sub-packets quantized by vector quantization. The spectral envelope parameters are encoded by vector quantization in selecting only a determined number of filters. The untransmitted energy values are recovered in the synthesis part by interpolation or extrapolation from transmitted values. Such a method may find particular application in vocoders.

Abstract: The present invention relates to a process for the phase amplitude demodulation of a received radar signal and to an implementing device, the process consisting in sampling the intermediate frequency signal at a sampling frequency fe such that fe is equal to &agr;B, &agr; being a number greater than or equal to 2 and B being the width of the pass-band, the intermediate frequency fi and the sampling frequency being in a ratio such that fi=(k±¼)fe, k being an integer. Application to coherent detection radars.

Abstract: A device for the operating of an automative cruise control system for an automobile vehicle comprises means to separate the travel of the accelerator pedal into two parts. The depressing of the pedal in the first travel part engages the automative cruise control system, the pull-back force of the pedal being smaller in the first travel part than in the second travel part. The device can be applied especially to vehicles equipped with means for checking the distance and/or the speed of obstacles located in the path of the vehicle, the pace of these vehicles being regulated or controlled as a function of the information on distance and/or speed given by said means. More generally, it can be applied to any vehicles equipped means of automative cruise control.

Abstract: A frequency hopping (FH) communication device and a frequency hopping method are provided. The frequency hopping communication device includes a first frequency hopping unit for receiving data to be transmitted, orthogonal frequency division multiplexing (OFDM) modulating the received data using the frequency of a subcarrier corresponding to a first frequency hopping code among the frequencies of a predetermined number of subcarriers, and outputting first frequency hopped data on which the data to be transmitted is loaded and a second frequency hopping unit for second frequency hopping the first frequency hopped data by mixing the first frequency hopped data with a carrier composed according to a second frequency hopping code. When jamming occurs, the frequency affected by jamming is restricted to a narrow bandwidth. Therefore, it is possible to reduce the influence of jamming and to easily restore data even though jamming occurs. Also, it is possible to improve the degree of concealment of data.

Abstract: Transmitter systems in which an output signal is obtained by the summation of signals with predetermined discreet levels given by several amplification cells. Given a signal to be sent with an amplitude A and a phase &phgr;0, a control circuit determines (&agr;) a number of amplification cells sufficient to obtain slightly more than the value A with the phase &phgr;0 but to carry out a phase adjustment (&bgr;) such that at least two of the cells are phase-shifted, one in advance and the other delayed with respect to &phgr;0, so that the total sum of the signals delivered by the cells gives the signal A, &phgr;0. Such transmission may find particular application to amplification cell transmitters with discrete output levels.

Abstract: A display device with a liquid crystal cell including a layer of twisted nematic liquid crystal placed between two polarizers and including, between the liquid crystal layer and each of the polarizers, a structure for compensating for cell contrast variations according to the observation angle which has an orientation in the plane of the cell. The pass directions of the polarizers are separated by an angle of 90+A degrees, in which A is not zero, and the orientations of the two compensation structures are separated by an angle of 90+B degrees, in which B is not zero. Such a structure may find particular application to a liquid crystal screen, especially for avionics.

Abstract: This semiconductor laser comprises at least two layers of optically non-linear material as well as a quantum well at least located within one of the layers of optically non-linear material. The thicknesses and optical indices of these two layers are such that the waveguide constituted by these two layers has a modal phase matching condition for the process of parametrical fluorescence between the pump wave emitted by the quantum well and the parametrical conversion waves.

Abstract: A bi-functional optical detector including a first active photoconduction detection element configured to detect light within first and second wavelength ranges, a first diffraction grating associated with the first detection element and configured to couple the light within the first wavelength range so that the first active photoconducting detection element detects the light in the first wavelength range, a second active photoconduction detection element configured to detect light within the first and second wavelength ranges, and a second diffraction grating associated with the second detection element and configured to couple the light within the second wavelength range so that the second active photoconduction detection element detects the light in the second wavelength range.

Abstract: A method for making CMOQ transistors and associated devices. The method is used to make transistors of a first type and a second type in CMOS technology in an active layer. The method etches regions of the active layer or making them inactive so as to define active islands designed to form sources, channels of determined width, and drains of the transistors of the first type and second type respectively, covers at least two active islands with an insulating layer and covers the insulating layer with a conductive layer, and sequentially etches all the gates of the transistors of the first type and then all the gates of the transistors of the second type. The associated devices includes CMOS transistor devices obtained by the method. Such a method may particularly find application to devices for the addressing and control of active matrix liquid crystal displays.

Abstract: A method for transmitting data packets having a heading followed by a data field. The data of the field is transmitted by groups of symbols. According to the OFDM technique, subcarriers modulated by the groups are generated. A frequency modulation of a carrier signal delivered by a linear ramp generator is produced with a set of modulated subcarriers. When the signal is received, mixing with a linear ramp results in subcarriers which are separated and then demodulated for supplying data. This is useful for transmitting data packets particularly in wide band networks.

Abstract: A receiver of a frequency-shift-keying, continuous-wave radar comprises at least sampling means taking real samples of the signals in each reception channel and extrapolation means, the extrapolation means producing fictitious samples synchronous with the real samples, the reception signals being formed out of real samples and fictitious samples. Application especially to radars fitted into automobiles.

Abstract: A system for the estimation of the complex gain of a transmission channel is designed for parallel type modulators/demodulators that can be used in digital radio broadcasting. The system includes a given number N of sets of interpolators to estimate the gain on a useful symbol from known symbols constituting gain references evenly positioned in the transmitted signal, each set of interpolators being adapted to a particular situation of reception, ranging from a stable single-path channel to a channel with high temporal dispersion and high instability. The outputs of the interpolators are coupled to a selection device programmed to choose the set of interpolators that gives the weakest estimated noise during a specified length of time. Such a system may find application to digital radio transmission.

Abstract: A method for the control of flows particularly within an ATM switch transmission network with a distributed architecture. The method distributes a specified number n of shapers to each input line card, a specific shaper being dedicated to the VBRnrt (Variable Bit Rate non real time) category flows as a function of the totalized mean bit rate, and n−1 other shapers being adjusted as a function of the available bit rate (AVCR) of the output ports.

Abstract: The present invention relates to a display device with a liquid-crystal cell comprising a twisted nematic liquid-crystal layer (40) placed between two crossed polarizers (46, 48) and comprising, between the liquid-crystal layer and at least one of the polarizers, a structure for compensating for the variations in contrast of the cell according to the angle of observation. This structure comprises at least two superposed negative uniaxial media such that the extraordinary optical axis of one medium (44, 42) is parallel to the normal to the cell and that of the other medium (43, 41) is inclined with respect to this normal on the one hand and with respect to the plane of the cell on the other. This compensating structure includes an additional layer (50, 49) of a positive uniaxial birefringent material.

Abstract: A method and apparatus for differential coding of blocks of images includes coding the difference between a current block of an image to be transmitted and one of four blocks of the reconstructed current image in the closest vicinity of the current block. The device includes a differential image coding structure having a quantifier coupled to a variable-length coding device, a predictor and a device for reconstruction of the transmitted image coupled to a first image memory. The device further includes a second image memory for storing image blocks previously reconstructed in the image preceding the current image.