Abstract: A circuit for generating a constant reference oscillation from a video signal affected by a time error, comprising, a cut-off stage for receiving the video signal affected by the time error and outputting sync pulses and vertical sync pulses, a first frequency divider connected to the cutoff stage for receiving the vertical sync pulses and outputting divided frequency pulses and a first comparator stage connected to the first frequency divider for receiving the divided frequency pulses. The first comparator stage has an output connected to an oscillator and the oscillator, in turn, has an output connected to a second frequency divider which is also connected to an input of the first comparator stage.

Abstract: A device for mechanically recording a signal having a bandwidth of several MHz on a receiving surface, particularly on a video disc, comprises, a rigid housing having a stylus receiving cavity with a piezoelectric transducer mounted in said cavity which is adapted to oscillate backwardly and forwardly. A cutting stylus is connected to the transducer and projects out of the housing cavity for cutting the receiving surface. Damping means are disposed between the transducer and the housing in the cavity and provide a greater resilience for movement of the transducer in the direction of oscillation than in a direction perpendicular thereto.

Abstract: The carrier is modulated over a definite frequency deviation range and is demodulated in an FM detector whose output voltage is used in an evaluation circuit to produce a switching pulse representing the dropout. The FM detector is constituted by a demodulator providing a digital output signal having a first value "1" within the deviation range and a second value "0" outside the deviation range. An evaluation circuit is connected to the demodulator and produces the switching pulse responsive to only the second value "O". The demodulator includes an retriggerable monoflop and an edge-triggered D flip-flop, and the FM carrier is supplied to the control input of the retriggerable monoflop and to a first control input of the edge-triggered D flip-flop. One output of the monoflop is connected to a second control input of the D flip-flop and the switching pulse is provided at one of the outputs of the D flip-flop.

Abstract: A process is provided for producing a grinding agent carrier comprised of a carrier body and a layer of grinding agent on the surface of the carrier body. The grinding agent layer is initially produced on a planar substrate by sedimentation from a suspension comprised of a suspension medium and grinding agent, and the grinding agent layer is then transferred from the substrate and bonded to the carrier body. The substrate is maintained in a horizontal position and the sedimentation is effected on the horizontal substrate from a liquid column of the suspension wherein the liquid column has a height in millimeters which is at most around 0.4 times the square root of the width in millimeters of the liquid column.

Abstract: A composite input video signal, having blanking intervals and including line sync pulses increasing the amplitude of the input signal, is applied to the circuit, is amplitude filtered, and is split into a BA-signal, which is fed to an adding stage, and line sync pulses which are fed to a monostable multivibrator which converts the line sync pulses into output pulses having an amplitude within the amplitude range of the filtered video signal, and these output pulses are also supplied to the adding stage. The output of the adding stage is applied to the input of a storage controlled by a timing pulse sequence from a timing pulse generator. The output pulses of the monostable multivibrator are supplied to a phase comparator having an input connected to the output of the storage through a gating device. The phase comparator supplies a variable to the timing pulse generator to control its frequency.

Abstract: In order to effect repeated reworking of a body, whose tip, during use, engages a record carrier track to guide a playback or recording member along the track, the reworking involving subjecting the body to successive reworking operations after successive periods of use, the tip of the body being worn down to a certain extent during each period of use and material being removed from the tip to restore its original shape during each reworking operation, the useful life of the body is effectively increased by adjusting the maximum removal depth occurring during each successive reworking operation as a function of the depth to which the tip is worn during the corresponding preceding period of use.

Abstract: In the production of disc recordings, the label portion therefor is formed by tracing a pattern of essentially circular grooves or arrays of dots and groove or dot-free areas in the location of the label portion, the grooved areas contrasting visually with the groove-free areas and the pattern being such that one type of area, preferably the groove-free areas, forms the legible characters and patterns to appear in the label portion.

Abstract: A matrix to be used for fabricating disc shaped record carriers is produced by illuminating a photolacquer layer with a laser beam while the layer moves transverse to the beam axis and by controlling the beam so that it simultaneously produces a succession of spots modulated according to the information recorded and a continuous strip narrower than the spots and serving to provide a track guide for the scanning element of a playback device with which such a record carrier is to be used.

Abstract: To prolong the useful life of a diamond guide element which serves to guide a transducer and which is provided with a contact surface via which the element in use bears against the surface of a record carrier while the carrier moves relative to the element, the element is constructed so that the direction of such relative movement corresponds to a high wear resistance direction of the diamond, and the contact surface thereof is periodically ground in an opposite direction in which it has a lower wear-resistance.

Abstract: A playback device for disc-shaped record carriers containing video signals stored in the grooves thereof which includes an arrangement which, in response to an applied power pulse, displaces the pickup, during playback, by a number of groove widths transversely to the direction of the groove.

Abstract: A matrix, which is to be employed for pressing foil disc copies carrying a spiral groove which is highly concentric to the axis of disc rotation, is formed by electrodeposition from a lacquer foil original which is cut to form a groove corresponding to such spiral groove and to form additional grooves deeper than the spiral groove and having a form that produces, on the matrix, sharp edges capable of directly cutting the outer periphery and center hole of a foil disc copy.

Abstract: In a pickup for the playback of a high density signal recording stored at the surface of a record carrier, which pickup includes a scanning element and a mechanical-electrical pressure transducer connected to the scanning element by a layer of adhesive, undesired vibrations of structural parts of the pickup during playback are prevented by providing at least that part of the surface of the pickup where the pressure transducer is connected to the scanning element with a layer of a hardened casting mass, which is applied in the liquid state in which it has a viscosity of between 5 and 50 cP at 20.degree.C. Preferably, the remainder of the surface of the pickup is also covered with such a coating, with the exception of the scanning surface of the scanning element.

Abstract: A demodulation system of a playback device for a carrier frequency signal containing both useful information in the zero passages of the signal and signal break-ins which occur in the playback device. The system includes a limiter for limiting in an asymmetrical manner a signal fed to it and a demodulator coupled to the output of the limiter. A highpass filter is connected between the limiter and the demodulator so as to couple the output signal from the limiter to the demodulator. The highpass filter substantially passes only the useful information portion of the carrier signal and suppresses any break-ins introduced into the signal.

Abstract: A pickup system for playing back signals stored on the surface of a carrier in a form providing an optically detectable property which varies as a function of the time pattern of the stored signals, the storage being constituted by undulations or variations in the reflectivity of the carrier surface and the pickup system employing a laser beam which is reflected in a manner controlled by the stored information. The system includes a laser radiation generating element forming part of an optical resonator which also includes the carrier surface so that the intensity of radiation oscillations in the resonator is influenced by the surface and varies as the carrier moves relative to the laser element. The system also includes an output member for converting such intensity variations into an electrical signal representative of the stored signals.

Abstract: A method of producing a record carrier with stored signals thereon and the record made thereby. The method comprises applying to a flexible record carrier hill and dale undulations which correspond to a broadband signal in the form of a frequency modulated carrier frequency oscillation, further applying at least one further signal of lower frequency superimposed on the broadband signal, and selecting an amplitude for the further signal such that in playback of the stored signals by a skid-shaped pickup operating by compression of the hills, even the lowest hills contact the skid-shaped pickup and are compressed thereby.

Abstract: In a recording or playback system in which information is stored along a spiral track on a flexible record carrier foil which rotates at a high velocity on an air cushion above a stabilization surface, and playback is to be effected according to the pressure sensing technique, the adverse effects of static electrical charges which can be created when frictional contact occurs between the foil and points on the stabilization surface are eliminated by providing the stabilization surface with a grounded electrically conductive region in the vicinity of the path followed by a signal transducer along a radius of the foil plane as it traces the sprial track and by causing the foil to be closer to the conductive region than to the mass of the transducer.