Abstract: The disclosed optical fiber sensor uses the effect of variation in the birefringence in a birefringent optical fiber as a function of the stresses and of the temperature. It has a linearly polarized, wide-spectrum source coupled to a polarizing-preserving single-mode optical fiber, along one of its neutral axes, devices capable of inducing coupling points being distributed along this fiber. A polarizer at 45.degree. with respect to the neutral axes of the fiber is placed at output of this sensor fiber. The output radiation is analyzed by spectroscopy, for example in a scanning Michelson interferometer associated with a detector. The detection by the interferometer enables the identification of the devices that are subjected to stresses. The same type of device may be used for the simultaneous detection of the stresses and/or the temperatures. The disclosed device can be applied notably to the monitoring and supervision of any installation in which strains have to be detected.

Abstract: A pick-up for electromagnetic energy radiation guided between at least two parallel ground plates includes a plane conductive tongue positioned between the two ground plates in a plane parallel to these plates and pointed in the direction of propagation of the guided electromagnetic energy, and obstacles interposed between the ground plates and the tongue converting the electromagnetic energy guided between the two ground plates, propagated in transverse electromagnetic mode, into an electromagnetic energy that is propagated in transverse asymmetrical electromagnetic mode in a strip line structure formed by the tongue and the two ground plates.

Abstract: The disclosed method consists in:method for estimating the motion of at least one target in a sequence of images, including: coefficients transformed by the Fourier transform;computing a matrix called a phase correlation matrix, each coefficient of which is equal to the product of a transformed coefficient of a first image, by the conjugate of a homologous transformed coefficient of a second image, divided by the square of the modulus of this product;computing an inverse transformed matrix of the phase correlation matrix, in applying the inverse Fourier transform;searching, among the coefficients of the inverse transformed matrix, for those coefficients having the greatest moduli;then estimating a translation vector for each target and a translation vector of the image background, on the basis of the order of the row and of the order of the column in which there are respectively located the coefficients having these greatest moduli.

Abstract: A method is disclosed for assigning radar recurrences to radials to be displayed.A converter has means receiving an antenna rotation signal (68 ) and a radar synchronization signal (SY.sub.R), and groups incident recurrences in radials to be displayed as follows:memorization of the incident radials at the rate of their arrival in one of the memories of a group of three with, as the case may be, grouping of the incident recurrence with the already memorized recurrence, with the number of memory being written in getting incremented by one unit at the first blip SY.sub.R following the reception of a blip .epsilon.; andreading of a memory during the reception of a blip .epsilon. in order to constitute a radial, the number of the memory to be read being obtained by deducting 1 from the number of memory being written in at this moment.

Abstract: A magnetic head employs a gap of magnetic material between two poles. The magnetic material of the gap has a saturation value less than the saturation value of the poles. When the gap material is not saturated, the magnetic field remains contained within this gap.

Abstract: The device improves the decoding of the replies in S mode deformed by multiple-path phenomena or by imbrication with replies in standard A or C mode. To do this, the device carries out the following in the reception video signal Log .SIGMA. of the secondary radar: determines a pulse level reference value of the data block of the reply by a study of the histogram of the presumed pulse levels of data and compares the level of the reception signal Log .SIGMA. taken at the middle of each time interval that may be occupied by a data pulse with the level reference value, a data pulse being detected or not detected according to the result of the comparison. Should there be a negative result in a baud period, it may recommence similar operations on the angle measurement video signal .SIGMA./.DELTA. if the secondary radar is a monopulse radar.

Abstract: A reading device of interferometric or polarimetric sensors including a main fiber on which a number of couplers equal to the number of sensors are placed, each coupler connected to a secondary compensation fiber, followed by a polarizer and a detector, thus constituting n elementary polarimeters.

Abstract: A reading device operates by the placing in interference of a reference signal, in the form of a fundamental wave train, with delayed wave trains constituting the useful signal. The device comprises an interferometer, a first branch (32) of which is traversed by at least said fundamental wave train (14), the first branch (32) being equipped, with means (37, 67, 87) for the generation of quantified delays of said fundamental wave train (14) with means (39) for the generation of a continuously variable delay of said fundamental wave train (14) over a range about each quantified delay value.

Abstract: The present invention is directed to a mode transformer for a microwave energy transmission circuit. This transformer is interposed between an electromagnetic wave source, operating in a predetermined frequency band, and a waveguide transmitting energy. This waveguide is excited by the electromagnetic wave source in a single chosen mode. The transformer has the shape of a conical tube whose large end is connected to the waveguide. The electromagnetic wave source is connected to the conical tube by a lateral opening. In the region of the conical tube where the excitation takes place the cross-section of the conical tube is smaller than that of the waveguide. At the center of the lateral opening, the cross-section of the conical tube is that which would be that of a waveguide of the same shape whose cut-off frequency, for the chosen mode, would be the central frequency of the working frequency band.

Abstract: The device for the dynamic measurement of the torque Ci of a polyphase self-synchronous motor comprises a sensor of the electrical angle between one of the phases and the axis perpedicular to the magnetic moment (APMM), circuits for the computation of the cosines of the angles (A, A-120.degree., A+120.degree.) between each phase and the APMM, sensors of current on each phase, and means to compute the torque Ci by application of the formula:Ci=k[i8.cos A+i2.cos (A+120.degree.)+i3.cos (A+120.degree.

Abstract: In a method of formation of channels for a sonar, after having sampled at a frequency T=1/4f.sub.0 (where f.sub.0 is the receiving center frequency of the sonar) the signals from the hydrophones of the sonar and having translated them to baseband, the signals thus translated are subsampled with a period T.sub.SE =kT (wherein k is an integer) substantially equal to 1.25 B, where B is the reception bandwidth of the sonar. A first set of signals is subsampled at identical times to form a frontal sector. Two further sets of signals are subsampled with delays between the signals from two adjacent hydrophones equal to T, which determines two side sectors adjacent to the frontal sector. The subsampled signals are then transmitted serially by the towing cable of the sonar device towed array and are processed in FFT circuits which allow to form in each sector a set of channels covering the sector.

Abstract: A luminous data display system is used to improve readability depending on fluctuations in the light environment. It has automatic means to adjust the luminance of the image produced on a screen. These means use a first sensor close to the screen to obtain an indication of the ambient illumination received by the screen, and a second sensor, preferably placed on the helmet, to appreciate the distribution of luminance perceived in the observer's field of vision. Circuits process the detected signal and a manual adjustment signal to produce a correction signal applied to the image video signal.

Abstract: A ring-shaped interferometer device containing optical means for phase shifting which act on the rays passing through the rings, these means containing an oscillator which delivers a periodic voltage of frequency 1/2.tau., in which .tau. is the time taken by a ray to pass through the ring and a saw-tooth generator whose resonant frequency is slaved to the non reciprocal phase shift.

Abstract: A linear hydrophonic antenna with an associated portside/starboard ambiguity removing device comprises three streamers placed in an equilateral triangle, with a center distance of the order of a third of the wave length which corresponds to the center frequency received. The density of the median streamer is notably greater than the common density of the other two streamers. Channels are formed in a standard way, and the received signals are phase shifted then added up so that the directivity associated with each channel shows a zero, either at portside or at starboard, the direction of which remains fixed despite the roll.

Abstract: This system enables the boresighting of the optical axes of a system comprising, for example: an infrared distance measuring device, a television camera, sensitive in the visible band, and a laser telemeter which does not emit radiation in the ranges of spectral sensitivity of the distance measuring device and of the camera. One embodiment includes:a collimated radiation source, associated with the laser;a wide-band collimator including, in its focal plane, a screen with holes cut out in it, constituting a reticle illuminated by an incandescent bulb, the surface of the screen being covered with glass micro-beads. The source associated with the laser forms a light spot on the screen, and this light spot is visible to the television camera. The holes form a reticle visible both to the television camera and to the distance measuring device. The distance measuring device determines the distance between the image of the reticle and a reference point on its image sensor.

Abstract: The present invention relates to processes for the construction of semiconductor lasers.The process according to the invention is essentially characterized in that it consists in forming a layer 1 of a laser semiconductor active medium, in forming an optical cavity 2 associated with this layer, in disposing, on at least a part of the surface of the layer, first 6 and second 7 layers of materials of impurities of opposite polarities, in causing diffusion into the active medium of at least a part of the two materials of impurities to form, in the first layer, a cylinder 8 axis substantially parallel to the axis of the optical cavity and formed of two semi-cylindrical half-shells 9, 10 of diffused impurities of opposite polarities, and in connecting two conductors 12 of the electrical energy respectively to the two half-shells.Application to the construction of a plurality of laser diodes on one and the same support substrate, to create a homogeneous and dense single laser beam.

Abstract: A device for setting up and routing telephone calls between subscribers of a radio-telephone network and/or a wired telephone network utilizes an automatic telephone exchange which is wired to the wired telephone exchange and connected to the radio-telephone network by a plurality of radio transceivers via a radio connecting unit. The radio connecting unit comprises a plurality of programmed processing units, each coupled respectively to a transceiver interface circuits, and a signal modem, controlled by the interface circuits. Each of the interface circuits have voice activity detectors for transmitting calls in an alternating mode between the subscribers of the radio-telephone network or between the subscribers of both networks. The programmed processing units are programmed with hierarchic restrictions to enable an organization of the radio-telephone subscribers into groups communicating on a same frequency and/or on a same transmission channel.

Abstract: A measuring circuit for the additive phase noise characteristic of a component in the vicinity of a carrier frequency. The measuring circuit is constructed of a central channel and two side channels. Each of these channels contains a model of the component to be characterized. Two phase detecting circuits are employed in which each processes an input signal from one of the side channels with an input signal from the central channel to generate signals which represent phase deviations between the two input signals. An intercorrelation circuit then utilizes the outputs from these phase detecting circuits to determine the characteristic additive phase noise of the component to be characterized by eliminating any additive phase noise superadded by other measuring circuit elements or induced by outside disturbances.

Abstract: The measurement of the stability of a radar in transmission/reception includes two steps. During a first step, video voltage signals leaving a phase detector of the radar receiver are measured at significant instants where said signals are capable of undergoing fluctuations. These signals come from a signal reflected by a fixed target and received by the radar. During a second step, an additional signal with pre-determined phase and amplitude is superimposed on the received signal in the receiver, in order to substantially cancel the stable parts of the voltage signals and to measure the fluctuations of the voltage signals thus obtained at said significant instants. The instrument to measure these fluctuations advantageously includes analog/digital converters with a small number of bits.

Abstract: Disclosed is an optical device for the processing of an optical wave by non-linear effects, comprising, on the surface, a guide and doping zones arranged transversally to the direction of the guide. The distribution pitch of these zones is equal to an even multiple of the length of coherence for the interaction envisaged. The length of each zone along the direction of the guide is equal to an odd multiple of the length of coherence.