Abstract: The invention provides cosine transform computing devices and image decoding devices and coding devices comprising such computing devices. One embodiment of a device for calculating monodimensional cosine transforms by blocks of 16 values comprises: three elementary computing devices for carrying out operations of the addition or subtraction type; two elementary computing devices for carrying out operations of the multiplication and accumulation type; a coupling device; and control means. The number of elementary computing devices is equal to the minimum number required for carrying out the transform calculations at the timing imposed by the arrival of the values to be transformed. Each elementary computing device is reused several times for the calculation of each transform. The coupling device is controlled by the control means for connecting the elementary computing devices in series in an order which varies at each step of the succession of calculations.

Abstract: The invention provides a method of forming electrodes aligned with respect to an implantation level in a substrate, including the following main phases:formation of a dielectric layer on a substrate;formation of semiconducting or conducting elements which are to serve as mask for implantation;implantation;formation of a layer of conducting or semiconducting material;cutting out electrodes from said layer and from the semiconducting or conducting elements.

Abstract: The interface of the invention comprises a power supply circuit (16) which is a symmetrical amplifier circuit, and a hybrid circuit (29) controlling the power supply circuit in DC and in AC. The hybrid includes a phase shifter circuit (44, 45) simulating long lines.Application: private telephony.

Abstract: A device for increasing the power output of a low-tension operated amplifier which is connected to a standard impedance loudspeaker and is powered at a voltage level which, in the presence of an audio signal, consists of the DC operating voltage for the set and an overlapping variable voltage which is proportional to the audio signal input to the amplifier.Thus, a high dynamic range is afforded for the output signal from the amplifer directed to the loudspeaker.

Abstract: A record player with a scanner for record disks is provided, where the vertical recording track angle .alpha. is to be placed within predetermined limits, but where, in general, the value of .alpha. is not known. The scanner comprises a transducer which generates useful signals and which is provided with elastically supported and therefore movable scanning elements. According to the invention, means are provided for determining the difference .alpha.-.beta. of the recording track angle .alpha. and of the tracking track angle .beta.. The angle difference determining means generate a voltage which depends on the longitudinal motion of the scanning elements moved during the useful modulation and which is displayed and/or employed for correcting the track angle. A record player with a tracking sound pick-up arm for the tracking of record disks is provided. Means for tracking a groove on a side of a record disk are disposed elastically supported and thus movable on the sound pick-up arm.

Abstract: Special effects are produced on video images by means of a method of geometrical transformation which can involve a translation, a rotation, an affine transformation or an effect of perspective. The method consists:in locating each point of the initial image by means of coordinates (X, Y, O) in a cartesian reference frame designated as a movable reference frame and related to the initial image;in representing each point of the initial image by a binary word;in storing the initial image in a storage device having two read address inputs and one data output, the function of the device being to deliver a binary word corresponding to the point with coordinates (X, Y, O) in the initial image when read address values X and Y are applied respectively to the two inputs:in causing each point of the transformed image resulting from an initial-image transformation to be located by means of coordinates (X.sub.3, Y.sub.

Abstract: A photocathode having a low dark current comprises a first layer consisting of P.sup.+ type semiconductor material which is transparent to all wavelengths of the light to be detected, a second layer consisting of P.sup.

Abstract: An automatic symmetry correction circuit is provided for a symmetrical current chopper. This structure includes two current channels controlled alternately by two signals of frequency f.A resonant LC circuit is tuned to the frequency f and energized by the currents passing through each of the two channels.A control circuit is coupled to the resonance circuit for adjusting the symmetry between the amplitudes of the currents flowing through each of the two channels as a function of the amplitude of the oscillations of frequency f generated by the resonance circuit.

Abstract: In a voltage-switching device for such applications as the control of electron tube grids in the field of radar or telecommunications, the total voltages to be switched are distributed at the terminals of a series-connected array of MOS field-effect transistors, thereby ensuring that each individual transistor is not liable to carry voltages in excess of such values which could result in transistor damage or destruction.

Abstract: A broadband amplifier comprising insulated collector vertical pnp transistors, a circuit device effective to improve frequency response, and a final stage comprising a so-called complementary pair formed of an npn transistor and a pnp transistor having emitters connected to each other and to an epitaxial layer n of the insulated collector vertical pnp transistor incorporated in the gain circuit of said amplifiers. The complementary pair afford minimization of the junction parasitic capacitances of the aforesaid vertical pnp transistor.

Abstract: The present invention concerns a device for generating a signal having a complex form through approximation, by utilizing straight-lined segments having variable slopes. It mainly comprises a generator for generating a constant current supplying in parallel a capacitor and a circuit which varies the current i.sub.1 flowing through the capacitor. The variation of i.sub.1 influences the current flowing through the capacitor. The output signal sampled at the terminals of the capacitor is thus a sequence of linear segments, the slope of which is discretely variable, and controlled by the circuit for varying the current i.sub.1.

Abstract: A substitution-permutation enciphering device.This device, adapted for transforming a binary word into another binary word, by a succession of substitutions and permutations, under the control of a key, is such that the substitution operations are performed by means of programmable or reprogrammable memories addressed by all or part of the word to undergo substitution, and by all or part of the key or of the parts of the key applied successively.

Abstract: The invention relates to multiple beam lasertrons. The n (n: integer greater than 1) electron beams of the lasertron are obtained from the same laser beam from which n secondary laser beams are extracted, by occultation, which are deflected respectively towards the n photocathodes of the lasertron.

Abstract: A miniaturized and integrated gyromagnetic device in which a center conductor is mounted between a pair of dielectric wafers and ferrite conductors to define a circular inner configuration. A pressure washer is welded to a square casing and mounts a magnet, the wafers, ferrite conductors and a pair of ground plates to absorb thermal expansion during operation.

Abstract: A radiological installation with dynamic compensation in the optical path of the image, with an optical attenuator with locally adjustable transmission placed at least in the vicinity of a focal plane in which the radiological image is formed situated upstream of the television camera of the image acquisition chain.

Abstract: The invention relates to a subscriber telephone set with amplified reception loudspeaker.To avoid distortion of the signals transmitted to this loudspeaker should the power supply of the line be insufficient, it is provided for the amplifier feeding this loudspeaker to have its gain controlled by a signal resulting from the measurement of current passing through a shunt regulator serving for supplying the amplifier.

Abstract: In one example of construction, a high-performance photocathode has the following structure:a transparent layer formed of P.sup.+ type semiconductor material having a forbidden band of sufficient width to ensure that this layer is transparent to the photons of the light to be detected;an absorption layer constituted by ten first sublayers formed of P.sup.

Abstract: A resistive solenoid magnet with homogeneous field is provided more particularly for NMR image formation.According to the invention, the magnet comprises several coils preferably Bitter coils and some parameters such as the lengths of the coils, the distances which separate them and their outer diameter are chosen for optimizing the power-mass product of the magnet.

Abstract: The invention pertains to programmable fast logic.The logic gate of the invention comprises two parallel-mounted inverters comprising one transistor and one saturable load. The second inverter is powered through a transistor, the electrode gate of which, linked to the drain, is joined to the drain of the first inverter which may have additional inputs (OR function). A triplet of three series-mounted logic gates comprises a programming input at the third gate, a re-looping output and, in the case of a sequence of triplets, re-looping inputs at the first gate of the first triplet. A programmable logic circuit is obtained by a sequence of series-mounted triplets which are all looped back to the first gate of the sequence. The programming is obtained by placing one or two programming inputs at the logic 0 level.Application: Programmable frequency divider circuits in which the ratios follow one another, one by one.

Abstract: The transformer comprises a primary coil comprising a conductive strip wound around an insulating coil base comprising a central part, two parts located at the ends of the central part with a roughly rectangular shape, the bigger sides of which extend along a second and a third direction which are mutually opposite. The length of the central part, measured along the initial direction, is determined so that the two ends have the directions of their bigger sides colinear in pairs when the central part is wound around the coil base. The two angles, formed at the points where the edges of the parts located at the ends intersect the edges adjacent to the bigger sides of the central part, are truncated to prevent the overlapping of the two ends when the central part is wound around the coil base.