Abstract: A helical tape recording and reproducing system which has longitudinal physical address track for recording physical address data relating to the physical layout of the tape and a logical address track that contains data relating to the content of the recorded helical tracks. Each address track has recorded segments with each of said segments containing data corresponding to a particular pair of helical tracks recorded in said helical recording area. Each segment has a multiple bit front field of a first predetermined timing synchronization bit pattern, a first predefined synchronizing word, a multiple bit segment information field of data, a second predefined synchronizing word and a multiple bit rear field of a second predetermined timing synchronization bit pattern.

Abstract: An arrangement involving apparatus and process damps vibrations, for example, rotary or linear vibrations, in a member to be damped, for example, in a supply tension arm forming part of a tape transport of a digital cassette recording system. The arrangement includes a limited angle torquer motor having an output connected to the member such that the presence of the detected vibrations to be damped imparts corresponding vibrations to the shaft (output) of the motor which, in turn, results in a corresponding back EMF voltage within the motor. A servo circuit connected to the input of the motor is designed to be responsive to the back EMF voltage within the motor, actually to an emulated version of the back EMF voltage, for driving the motor in a way to thereby damp the vibrations within the motor shaft which, in turn, damps the rotary or linear vibrations within the member itself. Approximately 20dBs of attenuation in vibration at the resonant frequency has been shown.

Abstract: Data is received at a variable input rate and recorded on a longitudinal medium in the form of fixed length data blocks with variable length spacing between the blocks, utilizing a transducer mounted on a rotating scanner drum. The input data rate may change between various recording/playback operations by a ratio of 1:100 or more, but during a particular operation it remains constant. The data blocks played back from the medium are sequentially stored in a memory at the internal data transfer clock rate, which is also utilized to control the scanner rotation. The data is read from the memory at a constant rate which is adjusted for each particular operation. A memory status control signal is m provided indicating a predetermined level of fullness obtained by the memory. That control signal is compared in time to a control signal indicating occurrence of the beginning of a next data block.

Abstract: A system and method for driving a stepper motor utilizing a near minimum amount of driving power is described. A stepping detector is utilized to determine whether the motor has actually stepped in response to a driving power applied thereto. When it is determined that the motor has stepped, the magnitude of the driving power is decreased. When the stepping detector indicates a stall condition, the driving power is increased. As a result, the motor operates near stall condition and power consumption is minimized. In the preferred embodiment during each consecutive step a different phase of the motor is deenergized to conserve power. By stepping the motor a voltage pulse is induced into the deenergized phase. The polarity and magnitude of that voltage pulse are examined after each step to determine whether the motor has actually stepped. The use of the deenergized phase to ascertain motor status eliminates the need for an external stepping detector.

Abstract: A simplified apparatus for providing a profiled tape tension is described which does not require a tape pack diameter sensor. Desired tape tension profile values corresponding to various tape pack diameter values are stored in a tape tension profiler. A control signal indicative of the rotational speed of a takeup reel is applied from a reel servo to the tension profiler which, in turn, changes a tension arm adjustment command in response to changes in the reel speed. The control signal has a known relationship to the tape pack diameter wound on the takeup reel. In the preferred embodiment the control signal is sampled by the tape tension profiler and the samples are used to address a PROM in which the desired tape tension profile values are stored. The thusly addressed tape tension profile values are applied as position command signals to the takeup reel servo which, in turn, changes the position of the tension arm accordingly, thereby obtaining the desired tape tension.

Abstract: A position servo system is described for positioning a member mounted on a spring. The spring provides a force opposing the motion of the member from an initial position. A position actuator, for example a motor, applies a force in response to a position request signal for moving the member to a desired position. A portion of the position feedback signal is applied from a position sensor to the motor as a positive feedback signal to compensate for the force of the spring. A steady state position error of the servo system is thereby substantially reduced to zero. A circuit and method for calibrating the positive feedback signal are also described.

Abstract: Disclosed is a joystick apparatus for effecting a plurality of variable voltage changes using one or more partial spheres concentrically mounted on the joystick shaft having longitudinally or latitudinally variable, light-detectable surfaces. A first light emitter/detector combination senses a first Cartesian coordinate axis tilting movement of the joystick control shaft and a second light emitter/detector combination senses a second Cartesian coordinate axis tilting movement of the control shaft to produce corresponding first and second voltages indicative of joystick position in the respective Cartesian coordinate directions. A handle portion of the joystick is rotatable and connected for carrying, in the preferred embodiment, a second spherical surface concentric with the first, and having a latitudinally variable, light-detectable surface. A third light emitter/detector combination senses the rotational movement of the shaft to produce a corresponding third voltage output.