Abstract: A magnetic reading device, of the type comprising multiple magnetic read heads, incorporates read heads each formed by a magneto-resistance element having a resistance which varies as a function of an outside magnetic field. The magnetic reading device comprises a network of line conductors intersected with a network of column conductors to form intersections at which a read head is provided. The first and second ends of each magneto-resistance element forming the read heads are respectively connected to a line conductor and to a column conductor of the corresponding intersection, and a control voltage is applied to the line and column conductors by a switching element for each line conductor, column conductors being connected to a current sensor. A simplification of the control of read heads results from this arrangement, while avoiding the effect of the heads not selected on the variations of current coming from the selected heads.

Abstract: The magnetic head of the invention is composed of several micro-heads each of which comprises, on a substrate (2'), a garnet (3') and two pole pieces (7, 8) separated by a narrow air-gap (9).

Abstract: In the matrix magnetic head of the invention, the ferrite pads (4 to 8) of the magnetic circuits of the micro-heads are arranged quincunxially, and each pad is joined to the four neighboring pads by poles (9 to 12). There are therefore twice as many micro-heads as there are magnetic pads.

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: A convergence adjustment device for color video-projectors having three monochrome tubes, each projecting an image of a give color on a screen. This device acts on the scanning of the second and third tubes for superimposing, on the screen, their images on that of the first tube. This device is of the digital type. It comprises a RAM in which correction values are stored corresponding to correction of the scanning currents for the different zones into which the image is divided. These values are restored in synchronism with the scanning of the zones during normal operation. The device also comprises a microprocessor for modifying, during the adjustment phase, the stored values as a function of the ordes issued by the user who makes this adjustment by observing the image. The user's actions in a manual mode affect only a single one of the zones. In an automatic mode, adjustments are effective on groups of zones.

Abstract: A geometry adjustment device for a color video projector having three monochrome tubes each projecting an image of a given color on a screen, comprising a geometry correction circuit adjustable by the user for providing, by acting on a single signal, vertical amplitude, vertical linearity and horizontal trapezoid corrections of the images projected on the screen by the tubes.

Abstract: The video image projection system of the invention includes two projecting devices formed by cathode ray tubes for projecting a green color onto a projection surface and two other projecting devices for projecting red and blue colors. The two green projecting devices project superimposed images. A circuit is provided for processing a video signal to supply a background signal without fine details to one of the green projection devices and a sharp contour signal to the other green projection device.

Abstract: The circuit comprise a switch controlled so that at each period of the AC voltage it is conducting for a period of time which depends on the desired output voltage, and a control of the output voltage slaved to an instruction or reference signal. The measuring signal of the control is the mean value of the voltage at the terminals of said switch during a period of the AC voltage. For establishing the mean value there is provided, an integrator whose input receives the voltage signal at the terminals of the controlled switch.

Abstract: The current which passes through the vertical deflector of a transistorized color television receiver is produced by a circuit comprising an active switch controlled and modulated at the line frequency and supplied by line retrace pulses delivered by the secondary winding of a line transformer. The voltage at the terminals of an assembly compring a capacitor in series with the vertical deflector has a constant sign which is independent of the current passing through the deflector. The same secondary winding of the line transformer supplies both the vertical scanning circuit and a rectifier circuit for producing a d.c. voltage, in particular for the supply of video amplifiers.