Ampex Corporation

Kudelski S.a.

Robert Boschgmbh

Kudelski Sa Fabrique De'enregistreurs Nagra

Stefan Kudelski

Jean-Claude Schlup

Ernest Rosselet

Eberhard Pertz

Error prevention in a recording and reproducing device with at least one

A tachometer assembly comprises two toothed rings (68, 70) in approximate axial register. The rings have similar peripheries of which the teeth (69, 71) are closely spaced in the axial direction of the rings. Magnetic flux in a path extending axially of the teeth varies as the rings rotate and is sensed by a coil (74) disposed coaxially of the rings.

Magnetic tachometer assembly

A control system for a motor which drives a tape capstan includes a capacitor (91) which holds a sample of a ramp signal which is sampled and restarted in response to tachometer pulses. The output of an amplifier (90, 100) which amplifies the difference between the stored voltage and a reference is integrated by a passive integrator (106, 92) coupled to the capacitor (91). The arrangement provides prediction of change of a discontinuous speed signal and is useful for slow running motors of low inertia.

Control system for an electric motor

A self-contained reel hub assembly for a tape transport. The hub assembly comprises a housing including a base and a side wall which upstands from and extends around the periphery of the base. Within the housing defined by the side wall is the rotor and the stator winding of a motor. The rotor drives a sun wheel which engages a plurality of planet wheels each of which protrudes laterally from the side wall of the housing. A rotatable hub is mounted on a central post extending upwardly from a frame member forming a top cover for the housing. The hub member includes a peripheral part which extends around the side wall of the housing and carries a ring of inwardly directed gear teeth engaged by the planets. The planets are linked by a carrier which permits limited movement of the planets relative to the carrier.

Reel hub assembly for tape transport

A tape driving capstan comprises a hollow post (39) a capstan member (36) and a rotor (57,58) which extends radially of the capstan member within a housing (49). The rotor carries permanent magnets (59) and a stator winding (66) is disposed within the confines of the rotor.

Tape driving capstan powered with a permanent magnet motor

A supply reel servo for a tape transport in which a motor-driven capstan of low inertia draws tape past a cylindrical scanning drum includes a tension servo arm which provides a signal denoting tape tension in a loop adjacent the supply reel. This signal is compared with a reference to develop an error signal to control the supply reel motor. The reference is modified in response to a signal which represents the energization of the capstan motor and accordingly the torque output thereof so as to provide automatic compensation for variation in tape tension at the scanning drum.

Reel servo for tape transport

A tape loop sensing arm comprises an arm member (6) which carries a rotary guide (5), comprising a cylindrical guide member (74) mounted on a spindle (65) which pivots on an axle (64) aligned radially with respect to the axis of rotation of the arm member.

Tape loop sensing arm and tape guide for magnetic tape recording and

A tape loop sensing arm is mounted for rotation with a plate (31) which extends into a core (37) and carries shaped lossy strips (34) for altering the quality factor of a coil (36) carried by the core.

Tape tension sensor and servo embodying same

To permit multi-color recording on metalized recording paper, in which an electrode burns off a metal layer covering a colored pattern, and to provide for ready association of the electrode with a specific discrete removal position and particular colors appearing thereat, the colors are applied in the form of a line pattern formed of elementary groups or sets (10, 16) of color lines, the color lines being applied in repetitive identical patterns to the carrier, without intervening gaps.

Method and system for thermally recording information on a metalized

To record images, including multicolor representation of colored images on electrosensitive coated paper in which a metallized coating is burned off from a substrate which may be either transparent or opaque, color element information is applied to the substrate, for example in form of dots, so that electrodes traveling across the substrate, or a comb electrode with multiple electrode tips, suitably energized, can expose, by burning off of the metallized coating, the underlying color dot. The color dots can be prepared in accordance with the well-known television color pattern or by applying yellow, green and red dots, in recurring periodic sequence, along the line to be scanned. For alignment of the recording head with the respective dot, markers are prederably provided on both sides of a recording strip, so that synchronization between recording pulses and actual color dots on the paper is obtained in spite of variations of the paper from a standard, occasioned, for example, by dampness or moisture absorbed by the paper.

Multicolor recording carrier and method of recording

To render the grey scale of recording on an electrosensitive recording medium (16) independent of voltage applied by an electrode (22) while maintaining a predetermined relationship between a command voltage (U.sub.c) and the resulting grey scale of the recording, the command voltage (U.sub.c) is compared in a comparator (44) with energy being supplied from an external source through a coil (32) having a primary winding (34) to which a capacitor (36) is connected in parallel to form an oscillatory circuit by a transistor (40). Upon controlling the transistor to conduction, for example in pulses supplied by a pulse source (48), energy will be stored in the L/C circuit 34/36 until the transistor is controlled to cut off when the command signal (U.sub.c) and a signal across a dropping resistor (42) indicates a predetermined relationship, for example equality, and representative of the energy required to burn out an area of the metalized coating corresponding to the selected grey scale. Transition of the transistor (40) to cut off or blocking state results in a pulse being transmitted to a secondary winding (50) coupled with the primary (34) of the coil, the secondary being coupled to the writing electrode. Thus, the voltage across the writing electrode (22) and the metalized coating (20) of the recording carrier (16) will be independent of the applied signal, but the energy content thereof varying in accordance with the applied signal. The result will be a burn-out trace, the width of which underneath the recording stylus varies (see FIG. 3) in accordance with applied energy, leaving variable amounts of non-removed metalized coating on the carrier, thus resulting in a grey tone, similar to half-tone printing, of the applied command signal.

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Le Mont-sur-Lausanne, Switzerland

Stefan Kudelski