Mcdonnell Douglas Corporation

Ampex Corporation

Ampex Systems Corporation

Glenn T Yoshida

David R Rodal

David N Larkins

Thomas L Helmers

A feedforward circuit applies a capstan drive current, or its equivalent, to the reel tension servo circuits whose associated reels are transporting the tape. The additional drive current to the reel drive motors increases the rotational velocity of the reels to maintain the same resultant acceleration between the tape driven by the capstan and the tape being transported between reels. Since the tape pack affects the gain of the feedforward circuit, a preselected average gain corresponding to the mean tape pack diameter is used to match different cassette sizes. A microprocessor may be used to provide the various signals and may vary the gain of the feedforward circuit not only in response to reel size but also in response to instantaneous reel tape pack diameter.

Tape transport control system with a feedforward capstan drive to the

An apparatus for controlling conditions in response to an operator input, the apparatus including a rotary knob coupled to the shaft of the rotor of a stepper motor having first and second stator windings, in quadrature, with each winding being center tap grounded to provide first and second winding portions for each winding. One pair of first winding portions are used for providing pulse inputs to a microprocessor on rotation of the knob, in either direction, via a pulse control system, with the microprocessor providing command signals to a braking control system, which includes a direct current power control source, which may be either a voltage or current control source. The power control source, in turn is in circuit relation with the pair of second winding portions. On command of the processor, a force or torque is applied to the rotor, by means of energization of the other pair of winding portions, with the force being in opposition to the direction of rotation of the knob, the force being in proportion to the applied power. Under control of a microprocessor, the force may be intermittently applied to simulate a mechanical detent arrangement, or a constant force for braking, either of which provides tactile feedback to the operator.

Interactive rotary controller system with tactile feedback

An optical system for recording information on or retrieving information from a rotating disc is disclosed herein. In this system a beam of light located on one side of the disc is directed onto and laterally across a given track of the disc. The track serves to contain the recorded information and, ignoring this information, is characterized by a predetermined light transmissivity curve in its cross-direction. An arrangement for maintaining the beam and given track in a fixed lateral position relative to one another as the disc rotates, even if the track moves laterally to a limited extent from its intended path of movement, is also disclosed herein. This position maintaining arrangement utilizes circuitry including light sensitive means, specifically two light detectors having trapezoidal light sensitive surfaces, disposed in optical alignment with the beam on an opposite side of the disc and responsive to the light passing through the disc from the beam for producing an electrical error signal corresponding in time to and substantially linearly in magnitude with limited lateral deviations of the given track from its intended position with respect to the light beam, this linear relationship resulting from the configurations of the light sensitive surfaces. The error signal is in turn utilized to vary the position of the initial beam for minimizing the lateral deviations relative to the beam.

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Cupertino, CA, United States of America

Glenn T Yoshida