Abstract: In a telephone installation, telephone rental data is loaded remotely into an independent station in the following manner.In response to a request for a call coming from the independent station and in the presence of a load request signal, a control means searches all the telephone rental data relative to the independent station as well as that indicating an order for the remote loading. A coding means codes with the help of a special key data which is secret. A processing means authorises the transmission of non-secret pubic telephone rental data as well as secret data thus encoded to the said independant station according to the order for the remote loading.At the independent station a decoding means deciphers the coded secret telephone rental data thus received with the help of the special key and a processing means stores the non-secret public telephone rental data thus transmitted and secret data thus decoded in a memory of the independent station.

Abstract: A method for the broadcasting of digital data, in channels to which multiple paths are assigned, the characteristics of which vary in time, with time-frequency interlacing and assistance in the acquisition of the automatic frequency control. This method is one of the type providing for the distribution of the data in the form of digital elements in the frequency-time space f-t and the transmission of frames of symbols each constituted by a multiplex of N orthogonal carrier frequencies modulated by a set of the digital elements and broadcast simultaneously, the method providing for the transmission of a pattern of frequency synchronization, recurrent in time. It can be applied notably for radio broadcasting at a high bit rate towards mobile receivers, and for example, to COFDM radio broadcasting.

Abstract: The invention relates to a process of identifying and authenticating data characterizing an individual, by verifying this data use a biometer. The process consists of recording on a memory card the data characterizing the individual owner of the card and of acquiring independently, by a biometer, the data characterizing this individual so as to obtain his imprint to compare it to that of the card and of proceeding to an identical processing of the imprint in the card and in the biometer, so as to establish a parity word and to exchange the parity words obtained by the card and by the biometer to compare them.

Abstract: The generator of the invention includes an initialization circuit (CI) delivering four initialization words (QI, RI, SI, TI), one calculation circuit (CC) composed of four sub-units (SQ, SR, SS, ST) corresponding to four generating polynomials of orders 5, 5, 7 and 7, and finally one output logic circuit (CS) delivering a pseudo-random byte sequence.Application for systems with access control, especially television systems.

Abstract: This process consists of depositing on a III-V or II-VI material (2) a mask layer (6), etching the latter in order to form therein openings (9) facing areas of the material on which epitaxy is to be carried out and then carrying out the epitaxy of the semiconductor layer (14) on said areas in an OMCVD frame by subjecting, at atmospheric pressure, the masked material simultaneously to vapours of chemical species of at least one III or II element and at least one V or VI element, as well as to vapours of HCl or at least one halide of a V or VI element, the elements III and V or II and VI of the chemical species and the halide being those which will form the semiconductor layer, said species being organometallic and/or hydrogen compounds. It is also possible, just prior to the epitaxy stage, to etch (12) the unmasked areas of the material, at atmospheric pressure, in the same frame as for the epitaxy using vapours of at least one halide of a III, V, II or VI element constituting the material to be etched.

Abstract: An apparatus for coding/decoding image signals processes sequential information signals in real time so as to compress the volume of data necessary for representing the corresponding image resulting in a minimum bit rate for transmission of the corresponding image using a transmission network. The coding/decoding apparatus includes a coding arrangement for coding image signals to be transmitted as well as a decoding arrangement for decoding the image signals received. The coding arrangement includes a local image coding loop for images broken down into blocks including a coder incorporating a transformation and quantization arrangement for coding the difference between each block of a local image and the corresponding block of a preceding local image. A decoder of the local image coding loop incorporates a reverse transformation and reverse quantization arrangement for reconstituting each block.

Abstract: The system disclosed includes a light source (12) able to emit an intense, coherent, monochromatic beam, called the control beam, whose frequency is equal to the center optical frequency of one of several frequency multiplexed signals, which has been selected, an optical coupler (14) for coupling the signals and the control beam and an optical switching device (16) having an active material with a non-linear optical response, whose passband is narrower than the intervals separating the frequency band occupied by the selected siganl. The device receives the light from the optical coupler and supplies a beam reproducing the information of the selected signal. The invention can be used in telecommunications.

Abstract: A device for compressing a digital audio signal, includes a device for allocating bits available for the transmission or storage of the signal, controlling means for the adaptive quantization of the signal, in order to enable a major reduction in the bit rate while at the same time preserving the quality of the starting signal to the maximum extent. The device includes means for allocating a specific number of bits for the expression of the coefficients of each frequency band of a transformed digital audio signal, as a function of a piece of auxiliary information corresponding to a description of the spectrum of the signal, said device being informed by means for the prior elimination of spectral components of said transformed signal as a function of a psychoauditive criterion.

Abstract: The antenna is preferably of the offset type and comprises plural thin and separable parabolic elements jointed into a parabolic reflector, and several substantially rectangular separable panels assembled into a prismatic lattice frame for supporting the reflector. The panels are substantially perpendicular to the lower base of the lattice and have curved upper edges formed in a duplicate mould according to the reflector and separable from the reflector elements. The antenna also comprises a telescopic elevation angle lifting mast and a circular aximuth positioner, both jointed to the frame and dismountable. The dismounted antenna is transportable in the form of standardized packages in the hold of long-distance airliner.

Abstract: The station, in particular a terminal, comprises an oscillator (OS) having a feedback loop (1) and a station inductor element (L10) suitable for conferring a working frequency to the oscillator which varies relative to a rest frequency. The station also includes a station processor connected to the oscillator and capable of processing variations in the working frequency of the oscillator. The portable object, in particular a memory card, includes an electronic circuit which is switchable between an inactive state and an active state in which it sets up a resonant circuit tuned on a frequency which is distinct from the rest frequency while remaining suitable for being coupled inductively with the feedback loop (1) at the rest frequency. The portable object also includes an object processor capable of switching the electronic circuit as a function of the information to be transmitted to the station.

Abstract: Method for obtaining an organic polycrystalline material having in particular electro-optical properties, said material obtained and an electro-optical modulator comprising said material.This method includes a stage (1) for preparing a powder having a size grading of 500 to 800 nm of an organic compound having a delocalized system of electrons .pi. and presenting a non-centrosymmetrical crystalline structure, as well as intramolecular load transfer groupings, a stage (2) for drying the powder under vacuum, a stage (3) for pre-pressing the powder under vacuum, and a hot stage (5) for the uniaxial compression of the dried powder under vacuum.This method enables polycrystalline materials to be obtained, said materials comprising elongated monocrystalline grains orientated according to a given direction.

Abstract: The device checks the connection of the conducting wires of a bus such as a bus distributed in a local area network. It comprises two test modules to be connected to the terminations of the bus. The first module comprises a voltage source and detects electric discontinuities in the pairs of wires, and an abnormal crossing of two wires of one and other pair when the second termination is directly connected to terminating impedances of the bus. The second module signals a crossing of wire pairs and crossings of the wires within a pair. These different tests are carried out by working switches and their results are interpreted as a function of the activating and deactivating of current sensors such as LED.

Abstract: The radio system embodying the invention comprises a central station and a passive terminal station. First and second data signals are transmitted between data processing units respectively connected to the central and terminal stations. The terminal station comprises a same low-cost circuit associated with a square two-dimensional antenna for detecting the amplitude of a first incident microwave emitted by the central station thereby recovering the first data signal and deriving, in response to the first microwaves, a microwave modulated in phase by the second data signal by means of a retroreflection of a second incident microwave. This second incident microwave is emitted by the central station to the two-dimensional antenna of the terminal station. The terminal station is of very simple design, is compact and can therefore be included as well as the corresponding data processing unit in a contact-free chip card.

Abstract: Disclosed is a method to achieve a sub-sampling of pictures, making it possible to optimize the spatial and temporal definition of the compressed signal, so as to enable a most faithful possible reconstruction of the picture received with said compressed picture signal and, if necessary, with complementary assistance data. A field of speed vectors is defined for at least each picture to be sub-sampled, and said pictures to be sub-sampled are sub-sampled by eliminating certain picture points, the preserved picture points being chosen so as to avoid selecting a picture point which corresponds spatially to the approximate projection of a source point preserved during the sub-sampling of the preceding sub-sampling picture, said projection resulting from the application, to said source point, of the associated shift vector.

Abstract: The telecommunications cable of the invention comprises a series of optical fibers which are preferably coated with respective colored identification layers, the fibers being split into modules each of which is enveloped by a thin supporting sheath that is easily torn, with different sheaths preferably being of different colors, the sheaths being in contact with the optical fibers, and a protective covering being in contact with the supporting sheaths.

Abstract: Method for coding a digital signal, a coder and decoder for implementing this method, a regeneration method and a corresponding regenerator. On each bit time, a detection is made of the possible presence of a binary pattern from any number "n" of binary patterns including at least two bits; the bit time is divided into "n" equal time intervals to which "n" temporal positions are associated; a correspondence is established between each of "n" binary patterns and each of "n" temporal positions; if one of the binary patterns is present, a pulse occupying a temporal position corresponding to the binary pattern is generated and the next detection for the possible presence of a binary pattern is made from the bit following the last bit of the binary pattern whose presence is detected.

Abstract: This e.g. Z-propagating, X-cut LiNbO.sub.3 :Ti splitter comprises an alternating delta beta directional coupler (39) able to introduce, in the absence of a voltage between its electrodes, a delta beta variation between its propagation constants, which is (a) independent of the polarization state of the guided lightwave and (b) such that the representative point of the coupler on its control diagram is the center of a segment parallel to the abscissa axis of the reference frame in which the diagram is plotted, and defined by two curves respectively corresponding to parallel states and crossed states of the coupler. Application to integrated optics.

Abstract: An audio signal is multiplexed into a video picture signal by converting the audio signal into a sequence of digital code words from which subwords are extracted relative to a video signal line frequency. The number of bits in each subword is determined as a function of the amplitude dynamic range of the video signal, and each extracted digital subword is converted to provide analog samples with amplitudes proportional to quantizing of the corresponding digital subword. These analog samples are used to amplitude modulate an active portion of the video signal corresponding to a picture so as to provide a "composite" signal having the format of the video signal.

Abstract: The stereoscopic convergence is adjusted in stereoscopic imaging equipment to increase or decrease the stereoscopic convergence angle. Two imaging devices are disposed symmetrically relative to a median optical axis to generate video signals representing images of an observed scene. Depending on the required stereoscopic convergence angle, two image "read windows" are positioned symmetrically relative to the median optical axis, each being defined by a first pixel and a last pixel of a processed image line. The first and last pixels of a processed line are disposed between the first and last pixels of a raw (oversize) image line, with the result that the video signals generated by the stereoscopic imaging equipment represent righthand and lefthand processed images in corresponding relationship to the raw image read windows.

Abstract: An optical detection device with a variable detection threshold. The optical detection device comprises at least one element having a heterostructure on a substrate, the heterostructure incorporating two conducting layers and, between the latter, a semiconducting layer forming a potential barrier with each of the conducting layers is provided. Excited electrons are formed when the heterostructure is illuminated by light radiation, whose energy is at least equal to the detection threshold of the heterostructure. This makes it possible to detect the radiation by an internal photoemission of electrons between one conducting layer and the other. The device also comprises variable biasing of the heterostructure, the biasing making it possible to vary the detection spectrum and threshold of the device. The optical detection device finds particular application to the detection of infrared radiation.