Abstract: An arrangement for the recording of a digital information signal, in particular onto a plate-shaped, metallic recording carrier with the aid of a penetrating element is specified, in which the latter preferably has a pyramid shape with three side surfaces and three edges. The edge (6) forming the runner of the penetrating element lies, in its projection onto the recording carrier, in the direction of the velocity vector at the point of recording. The edge forms with the velocity vector an angle of >135.degree.. The projections of the two further edges onto the recording carrier lie perpendicular to the velocity vector. With the aid of such a penetrating element, an engraving of a digital signal is possible, which is read out by a laser beam.

Abstract: A process and an apparatus are specified for recording a digital signal onto a recording carrier (4), in particular a signal for recording in compact disc data format, in which an engraving or cutting stylus (2) is pressed substantially by dead weight alone against the recording carrier (4) and, in operating mode, describes a path which lies beneath the undeformed surface of the recording carrier (4) during an indentation to be engraved and on or above the undistorted surface of the recording carrier (4) between two indentations, the common center of gravity position of the engraving stylus (2) and positioning element (1) connected rigidly to it remaining substantially stable in position.

Abstract: A method for producing a prerecorded disk-shaped die is specified in which the information signal is recorded onto a metallic recording medium. According to the invention, the information carrier layer consisting of base metal is first vapor-deposited onto a glass base. Then the information signal is recorded onto the surface of the information layer with the aid of a cutting or stamping tool. Following this, a metallic interlayer of precious metal is galvanized on, onto which another base layer particularly of metal, is then galvanized. After the glass base has been mechanically separated, the information carrier layer can then simply be removed by a chemical medium which does not attack the interlayer. The method according to the invention is particularly suitable for producing dies for digital sound recording according to the compact disk process.

Abstract: An arrangement is disclosed for cutting information into a record carrier made of metal, particularly of copper by means of a diamond, with the diamond body being adjusted for cutting under a canting angle and being ground in such a manner that, deviating from the prior art manner, the cutting edge does not coincide with a diamond zone of optimum hardness but deviates from the optimum position by an angle which is preferably equal to the canting angle.

Abstract: Method and apparatus for producing a mechanically reproducible recording in a metal disk record by operating an electrically excited cutting stylus to cut a modulated groove in the record, orienting the cutting stylus to be driven at a tracking angle of less than 5.degree., and electronically compensating recording distortions caused by this tracking angle.

Abstract: A stylus assembly for cutting information in a recording medium comprises a stylus having a leading face; a mount comprising a bar having a groove extending in a face of the bar generally parallel to the length dimension of the bar. The stylus is received in the groove such that the leading face of the stylus is oriented away from the groove and slightly projects therebeyond in its entirety.

Abstract: A device for removing a chip produced during cutting of information into a record carrier, particularly a metallic record carrier, wherein the cut chip is removed by means of suction air and the magnitude or pressure of this suction air is controlled in dependence on the depth recording component of the recording.

Abstract: Apparatus for recording an information signal on a metallic record carrier. The information is impressed on the carrier by cutting a groove therein by means of a stylus, the groove being characterized at each point by a slope or modulation pitch angle. The stylus has a longitudinal axis, a leading edge substantially parallel to this axis and a trailing edge. The angle between the longitudinal axis of the stylus and a normal to the surface of the record carrier is greater than 10.degree. and not more than a value which would make the angle between the trailing edge of the stylus and the surface of the record carrier less than the maximum modulation pitch angle. The stylus is movably attached to a fixed structure by a mounting member and is electromagnetically excited by a driving member to shape the grooves in the record carrier in accordance with the information signal.

Abstract: A device for centering a record disc with respect to a turntable, in which the disc is successively radially centered and axially positioned relative to the turntable, which device includes a centering shaft engageable with the disc to effect preliminary radial centering thereof, is additionally provided with further radial centering elements mounted to engage a disc after it has engaged the shaft and to undergo yieldable movement relative to the turntable in the axial direction of the disc under the influence of its engagement with the disc for effecting final radial centering of the disc, and a magnetic attracting unit operatively associated with the disc and the turntable for axially positioning the disc after it has been finally radially centered.

Abstract: A playback instrument for a record disc, the instrument including a turntable for supporting the disc to be played on which the disc is centered by means of a central bore, is provided with two annular, concentrically disposed, radially spaced flat bearing surfaces mounted on the turntable for the disc, the surfaces forming a rigid support, one bearing surface being disposed in the vicinity of the location of the center of such disc and the other bearing surface being disposed radially to the outside of the one surface at a distance from the location of the center of such disc, and disc holding components provided for exerting on such disc an attracting force of such magnitude as to cause the disc to contact the bearing surfaces over the entire area thereof.

Abstract: In an apparatus for forming a groove which is modulated to present an information track in a signal record carrier having a copper surface portion by cutting such groove into the copper surface portion by means of a cutting stylus, the stylus is formed to present, during cutting, a rake angle of between 10.degree. and 20.degree., and the copper constituting the surface portion into which the groove is cut has a Vickers hardness of between 110 and 300, and preferably between 120-220.

Abstract: A method and apparatus for reducing a resonance peak in a piezoelectric transducer for mechanically recording a signal having a band width of several MHz, in particular on a video disk comprising, applying a countercoupling current across terminals of the transducer for counteracting a current flow in the parallel capacitance of the transducer. A circuit of the invention comprises a piezoelectric transducer having two terminals and including in series a characteristic inductance, capacitance, and resistance, and a parallel capacitance characteristic in parallel to the series characteristic, a signal generator for generating the signal to be recorded, a transformer having a primary winding connected to the signal generator and a secondary winding connected to one terminal of the transducer with a symmetrically disposed central ground connected to the secondary winding.

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: 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.