Tracking control apparatus using digitized vertical synchronizing signal

摘要

A tracking control apparatus for a disc reproducing apparatus comprises a circuit including a head for reproducing an FM video signal from a disc recorded with the FM video signal on concentric tracks or a spiral track formed on a recording surface thereof, a moving mechanism including a motor for moving the head in a radial direction of the disc, an extracting circuit for extracting a vertical blanking period portion of the reproduced FM video signal, a circuit for sampling and holding a D.C. level of the vertical blanking period portion and for obtaining a digital value indicative of the sampled and held D.C. level, a memory for storing the digital value, and a control circuit for controlling a write-in and a read-out with respect to the memory. The control circuit supplies a control signal to the moving mechanism to move the head to a plurality of positions which are mutually separated by predetermined minute quantities with respect to one track pitch and writes a plurality of digital values into the memory which plurality of digital values are obtained when the head assumes the plurality of positions. The control circuit obtains a maximum digital value from among the plurality of digital values stored in the memory and supplies to the moving mechanism a control signal for moving the head to a position where the maximum digital value is obtainable.