Sperry Rand Corporation

Wilbert Cleon Anderson

Vernal Wynn Thompson

Vaughn J Jenkins

David Robert Anderson

Lawrence Walter Urry

Apparatus for generating elevation and azimuth reference signals for use in demodulating a tracking error signal to provide elevation and azimuth error components for use in adjusting the position of a tracking conical scan radar antenna, includes a template ring having a notched periphery and being attached to a rotatable nutator of the antenna such that its peripheral notches are in a predetermined angular phase relationship with a reference position on a feed horn attached on the nutator, during rotation of the feed horn with the nutator. The apparatus further includes an optical transducer and electronic circuitry coupled thereto for producing the reference signals from a signal generated by the transducer in response to rotation of the ring with the nutator. As the ring rotates with the nutator, its notched periphery makes or breaks a photon path between light beam generating and sensing elements of the transducer. The sensing element then generates the signal which is received by the electronic circuitry. In addition to the two reference signals produced by the circuitry, a sync signal is generated and used internally within the circuitry to insure that the reference signals produced are in a proper phase relationship to the reference position on the feed horn of the nutator during rotation thereof.

Reference signal generating apparatus

An antenna tracking system in which attenuation of gain in the azimuth tracking circuit as a function of the angle of elevation of the antenna is compensated. A correction circuit is provided in the servo loop for amplifying the azimuth error signal and rate gyro signal by an amount equal to the secant of the elevation angle.

Secant correction circuit

A tape reel servo control system for use with a tape transport system wherein tape loop position within vacuum loop boxes is maintained by digital techniques as opposed to analog techniques. In normal operation when the tape loop deviates from an equilibrium position in one direction within a loop box, its associated reel is accelerated to move it back to its equilibrium position by means of a series of motor drive pulses whose pulse lengths are determined by the count registered in a counter wherein the count is varied in accordance with the difference between actual and required acceleration of the reel. When the tape loop deviates from the equilibrium position in the other direction, the reel drive motor is braked by electronically shorting its terminals until the tape loop moves back to its equilibrium position. When the direction of tape movement is changed, means are provided which override the normal control of the system and prevents tape damage by overrun into or removal of the tape from its associated loop box by applying a combination of motor braking and plugging current to the motor drive.

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Salt Lake City, UT, United States of America

Wilbert Cleon Anderson