Abstract: A controller for initiating operation of a video tape recorder and for terminating operation when its power consumption drops to a predetermined level utilizes a power transfer circuit for coupling the recorder to a source of energizing potential. A normally open switch, included in the transfer circuit, responds to an actuating signal developed by an operational amplifier, which amplifier is activated by an enabling signal from a preset clock. Thereafter, the amplifier is controlled by a derived signal having an amplitude proportional to the current drawn by the recorder. When the energizing current for the recorder drops below a predetermined level, the derived control signal is now of insufficient amplitude to maintain the amplifier in an operating condition, as a result, the actuating signal for switch is interrupted and operation of the recorder is terminated.

Abstract: A matrix of four photoreceptors is arranged to develop output signals representing information stored in a video disc as well as error signals for maintaining proper tracking registration of the reading beam with the storage track of the disc. The matrix enables all four photoreceptors to contribute to the development of the output signals and permits separate treatment of high frequency and low frequency signal information for improved results with respect to response and signal-to-noise ratio.