Abstract: 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.

Abstract: 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.