Abstract: The invention relates to an optical fiber measuring device of the type in which variation of a measured parameter causes a difference of progression of light waves in the optical fiber. Such a device permits measurement of speed of rotation, or of current and magnetic field. The device includes an electronic device for digitally processing a signal indicative of phase shift of one light wave relative to another, the light waves propagating through a preferably monomode optical fiber in a SAGNAC ring interferometer, modulated by a phase modulator.

Abstract: A pipeline-type serial multiplier having a cellular structure, each cell comprising an adder which operates on 3 one-bit data x, y, c and which determines the result v modulo 2 and the carry c.sub.o of the addition of x, y, and c. Each adder simultaneously determines a data c.sub.1 which is the modulo 2 result of the addition of x, y, c.sub.o. This enables the exact final result of a multiplication of a data A of n bits by a data B of p bits to be obtained in two successive segments: a segment L which is formed by the p bits of lowest digital weight and a segment H which is formed by the n bits of the highest weight. The output rate is F/n, where F is the clock frequency. The multiplier circuits can be cascaded under the control of an external signal. They can also be connected in parallel in order to add the results of two multiplications.

Abstract: An ultra-fast sample-and-hold circuit for the processing of analog signals comprises a diodes bridge: an input signal VE is applied to the input point and copied at the output point; the output signal is memorized in a capacitance. At the midpoints of the bridge, two current sources are applied. The voltages at the midpoints are servo-linked, in the hold mode, to the output voltage by means of a voltage follower and diodes mounted diagonally across the bridge, the two switches of the current sources being controlled by a signal clock signal. It is applied to signal processing chains in instrumentation, radar and telecommunications.

Abstract: A processor of images of objects described in three dimensions for determining parameters of pixels on a display screen. The processor possesses inputs for parameters of convex polygons describing the objects in a frame of visualization and determines from the parameters of the polygons the parameters of the pixels of a transformed two-dimensional image of that object. In order to eliminate concealed faces of objects displayed on the screen from a perspective view, the processor selects and stores the parameters of all the elements of the transformed image which are closest to the plane of visualization (the display screen). The image processor is noteworthy in that it serially processes, by pipeline organization, the parameters of a set of segments which constitute the intersections of the set of polygons with each line of visualization of the visual display device, a plurality of segments being processed simultaneously.

Abstract: Process for real time signal processing for side-looking synthetic aperture radar systems, the signal consisting of sample sequences corresponding to given spacing gates. For each spacing gate an operation corresponding to an auto-correlation is directly performed on the radar signal, this relating to a product signal of a sample by a phase term varying quadratically with the rank of the sample, which supplies an estimate of the Fourier components of the radar image for each gate.The invention also relates to a circuit for processing the radar signal in real time for performing the aforementioned process.

Abstract: Ceramic material for a low temperature direct heating electron gun cathode, wherein it is constituted by a mixed ceramic material of a hexaboride of a refractory material consisting of at least one substance with a high emissive power from the group consisting of La, Sr, and Ba hexaborides and a conductive material, boron carbide, having a resistivity higher than that of an emissive substance, the structure of the ceramic material resulting from its production by cofritting of the said components.

Abstract: A method of and apparatus for regulating an electron-beam welding generator of the kind having three electrodes viz: a cathode, a Wehnelt electrode and an anode. The method is characterized by a suitable combination of two methods of regulating an electron beam welding gun. One of these methods includes varying and regulating the very high voltage while maintaining the voltage applied to the Wehnelt electrode at the potential of the cathode (operation of the "diode" kind). The other method includes holding the very high voltage constant while regulating or programming the welding current by means of the voltage to the Wehnelt electrode (operation of the "triode" kind). The variations in and regulation of the very high voltage are controlled by an induction regulator associated with a thyristorized regulator.

Abstract: A cathode for an electron gun in which a lanthanum hexaboride cap has an internal recess which accommodates a pyrolytic graphite heater element. The cap is cup-shaped, while the heater element is in the form of a frustum of a cone and is resiliently maintained in abutting relationship with the cap by a corrugated tubular member and an assembly of rigid tubes. A cylindrical shell surrounds the periphery of the cap, and a pair of generally conical shielding elements are located in position to intercept stray thermal radiation from the heater element. All of these cathode components are supported in coaxial relationship with each other within the electron gun.

Abstract: The sealing device is adapted to a vacuum enclosure which can be applied against a bearing surface and essentially comprises at least two concentric seals mounted in a support which is rigidly fixed to said enclosure and extending parallel to the bearing surface. One seal consists of a solid annular seal made of flexible material and placed near the outer edge of the enclosure. The other seal consists of a hollow and inflatable annular seal which is placed near the inner edge of the enclosure and is connected to a source of fluid under pressure by means of a closable duct.

Abstract: A vacuum enclosure rests on two parts to be seam-welded by the electron-beam welding technique and surrounds a support for an electron gun. The support is made up of two separable elements, the first element being constituted by a frame applied in vacuum-tight manner against the parts to be welded by means of a seal fitted on one face, the other face being applied against a flange of the second element which forms a bell-housing and is applied against the frame.

Abstract: An electron gun which is displaced on a carriage relatively to two abutting cylindrical sleeves is guided so as to produce an electron beam which travels along the line of junction, the carriage being housed within a vacuum-tight enclosure which is applied against the sleeves on each side of the junction line. The cylindrical sleeves are supported and displaced in rotation about a horizontal axis with an equal range of motion and at a speed of opposite sign with respect to the linear speed of the carriage. The carriage thus remains motionless in a position such that the electron beam is continuously vertical.