Abstract: The information is recorded in the form of variable-length alterations (l.sub.0, l.sub.0 +N.DELTA.l), for example in the form of localized ablations of a thermosensitive layer of the medium. This type of coding of the information is sensitive to imprecisions in the form factor which are due to the non-linearity inherent in the recording method used. The method according to the invention consists in recording marks (M.sub.1, M.sub.2) serving as length reference, from place to place. These marks (M.sub.1, M.sub.2) are recorded at the same time and in the same conditions as the information proper (d.sub.1, d.sub.2, d.sub.3). During the read process, they serve as length references for the associated information area, and after conversion into electrical signals as time reference.

Abstract: The invention relates to a programmable transverse filter required for the matched filtering of signals with very wide passband. The signals to be filtered modulate one or more optical carriers (F1) in a modulator (MOD). Each carrier is distributed over several channels by a distributor (DIV). A delay creation circuit (CR1 to CRn) is provided in each channel. These channels are next summed after having been correctly delayed and assigned a coefficient characteristic of the signal to be detected.

Abstract: A magnetoresistive detector comprising a stack of layers having different magnetic characteristics (magnetic metal multilayers) wherein there is provision, under the effect of an electrical field, for a transfer of electrons perpendicularly to the layers. To ensure several perpendicular transfers through the same stack of layers, this stack is enclosed between two electrodes, and the electrical conduction of the entire piece is interrupted by a cutting out of the structure in the form of teeth in a Greek key pattern.

Abstract: The invention concerns precision analogue-digital converters. For the fine conversion, supplying the low order bits (B0 to Bk) for an analogue voltage Vin to be converted, three ordinary differential amplifiers (ADA, ADB, ADC) are used connected to three voltage references VR(i-1), VR(i), VR(i+1). These three amplifiers supply differential output voltages (VAa, VAb, VBa, VBb, VCa, VCb) that vary as a function of Vin according to normal transfer functions for differential amplifiers. Intersection points of these various transfer curves are detected in interpolation circuits (firstly CIT1, then CIT2, etc). These intersection points are used as intermediate voltage references between the main references. Comparators (CMP0 . . . CMPk), placed at the output of interpolation circuits supply bits (B0 to Bk) indicating the value of Vin with respect to each of these intermediate references.

Abstract: A frequency divider, constituted by N divide-by-two binaries, comprises logic circuits that enable the generation of a signal of the end of the frequency division by means of the change in state of the most significant bit generated by the Nth order divide-by-two binary. A binary code C representing a decimal integer value V is applied to the divider circuit. The frequency divider comprises circuits that enable the performance of a variable order division (V+1, V, . . . V-p, where p is a whole number greater than or equal to 1 and smaller than N-1) for one and the same binary code C.

Abstract: A color display device comprises a source of light simultaneously emitting several ranges of chromatic components and a spatial light modulator comprising several dots, each dot comprising at least one sub-pixel per range of chromatic component to be displayed. Between the light source and the spatial light modulator there are provided at least one chromatic separator angularly separating the light of the different chromatic range along different directions, a lens focusing the light of the different chromatic ranges at distinct points or along distinct lines contained in a determined plane, at least one spatial filter located along this determined plane and selectively filtering the light of the different chromatic ranges, and an array of lenses, each enabling the focusing of the light of each chromatic range substantially on a sub-pixel.

Abstract: An excitation stage having a predetermined number of semiconductor-based amplification modules parallel-connected at the input of a coupling device to couple the outputs of the amplification modules to the input of the transmission tube, as well as a diode-based limiter device positioned inside the coupling device to limit the pulses that short-circuit electrodes of the transmission tube appearing at the output of the coupling device.

Abstract: A transducer contains at least one layer of a composite material containing particles of a conducting magnetic material in a non-magnetic and insulating or semiconductor matrix material and two electrodes deposited on at least one face of the layer for measuring resistance of the layer.

Abstract: According to an embodiment of the invention the discrete or integrated electronic components are encapsulated, each in a package, for example a plastic one; the packages are then mounted on a printed circuit board, for example an epoxy one. The components and board as a whole are covered with a relatively thick first layer consisting of an organic compound and ensuring a levelling function, followed by a second layer such as an inorganic metal compound, the function of which is to ensure the hermetic sealing of the whole.

Abstract: A frequency/phase detector for a reference signal with a fixed frequency and a second signal with a variable frequency comprises essentially a frequency discriminator, already known, in which the output signal of a frequency-dependent phase-shifting circuit centered on said fixed frequency is applied, not directly to a demodulator circuit but through a summing circuit that receives in addition said reference signal.

Abstract: The system for wireless transmission of medical data comprises a piece of transmission equipment carried by the patient which comprises a unit for differential amplification and band filtering, a unit for rejection of interference noises, particularly the sector and its harmonics, existing in the band of the useful signal, an amplification circuit with automatic gain control and a modulator receiving a carrier frequency, for example microwave at 2.45 GHz and the useful signal, in analog or after a digital conversion and optional processings. The system also comprises a suitable receiving station. The carrier frequency can be either generated in the transmission equipment, or in the receiving station which then transmits the nonmodulated carrier for the transmitters that are associated with it.

Abstract: The invention relates to a method and system reading data recorded in the form of tracks on a magnetic recording medium. The recorded data is read by a row of read heads greater in number than a number of data tracks. The system of the invention does not require the read heads to follow the data tracks when reading recorded data, and allows a magnetic tape to be read even if the positions of the data tracks relative to the read head positions are unknown. The reading system of the present invention finds particular application in the area of reading high density recorded magnetic tapes.

Abstract: A method for dual-standard coding of very low data-rate images and a coder-decoder system for implementing the method, wherein images can be transmitted with low spatial "Quarter of Common Intermediate Format" (QCIF) resolution and with high time resolution according to a first standard, or with high spatial "Common Intermediate Format" (CIF) resolution and low time resolution according to a second standard.

Abstract: A process and a device for inspecting glass including the use of a laser to illuminate successive cross section planes YX of a piece of glass to be inspected by relative displacement of a light curtain formed by the illumination source. A camera detects a reflective radiation emerging from the piece of glass in an observation direction which is oblique to the plane YZ of the light curtain in order to form images on the camera which include two lines corresponding to the upper and lower faces of the piece of glass and any possible luminous points situated between these two lines which would correspond to inclusions within the thickness of the glass.

Abstract: The invention relates to integrated circuits and their manufacture.A process is described for producing electrodes juxtaposed very close together, such as those encountered in charge-coupled shift registers. According to the invention, a first polycrystalline-silicon layer (14) is deposited and a localised oxidation is performed over a small width, in order to tcwtcwdivide the layer into two electrodes (15 and 17). The layer zone which has been oxidised between the two electrodes is then totally deoxidised, in order to produce a hollowed-out space in which it will be possible to house a third electrode (38). This third electrode, also made from polycrystalline silicon, is deposited after a slight insulating layer has been reformed on the side walls of the electrodes 15 and 17. As the width of the hollowed-out space between the two first electrodes is small, a polycrystalline-silicon overthickness is formed.

Abstract: The invention relates to a device for locating noise emitters with an antenna comprising passive sensors. In a preferred variant, the antenna consists of N acoustic buoys each comprising a pair of hydrophone dipoles exhibiting a double-eight directivity diagram. Each buoy comprises a compass providing a signal K.sub.n representing the heading relative to magnetic North. The pairs of signals (a.sub.1 -b.sub.1 to a.sub.N -b.sub.N) are subjected to a rotation by the angle K.sub.n. The signals are next digitized and the number P of noise emitters estimated. The locating of these noise emitters can be performed according to two variants (8, 9).

Abstract: Disclosed are a device for the detection of S mode responses received by a secondary radar receiver and its use for the filtering of the pulses contained in this response. The device furthermore comprises means to detect a signal S, means for the real-time computation of the mean values of magnitudes characterizing the pulses that belong to the response, and means for the filtration, by comparison, of the values of the magnitudes measured on each pulse detected with the mean value of the corresponding magnitude.

Abstract: The system is designed to be mounted in a air pilot's helmet. It uses a confocal assembly with a first parabolic mirror and a second parabolic mirror, placed downline of a collimation objective which gives a collimated radiation. The first mirror is totally reflective and the second mirror is semi-transparent to simultaneously transmit, by reflection, the collimated radiation and, by transparency, for example the view of the external landscape. These two mirrors are integrated into the ends of a plate with two parallel faces. The collimated radiation penetrates the plate by one of the parallel faces, gets reflected on the first mirror, undergoes a succession of total reflections on the parallel faces and then gets reflected on the second mirror before leaving the plate, still doing so through one of the two faces.

Abstract: The invention concerns H-bridge type power amplifiers and their blocking means.The memory effect of the capacitive impedance of control inputs of each of the two blocking transistors-in the H-bridge is used to block and unblock the amplifier synchronously with the amplifier input signal: a first switch and a semi-conductor element are placed in parallel with each other, in series with each of these control inputs, such that the blocking of the blocking transistor necessitates the opening of the first switch under the control of the blocking signal, and is dependent on the sign of the charge carried by said capacitive impedance; a second switch controlled by the half periods of the input signal only enables the first switch to close and therefore unblocking of the considered blocking transistor for half periods that are not amplified by this blocking transistor.

Abstract: Disclosed is a method for the manufacture of a waveguide or a part of a waveguide from a casting, said waveguide comprising at least one part along which two parts of walls of the waveguide, a first part and a second part, must remain parallel to each other, with a spacing between them that is equal to a distance X with a tolerance value of x, the caster's tolerance value for the dimension X being f, wherein the part coming from the casting process is conformationally shaped with at least one of its first or second walls comprising embossed features, and wherein these embossed features are reduced by passes with a tool that is pushed or drawn in parallel to the first and second walls. FIG. 1.