AUTOMATIC TRACKING SERVO CONTROL SYSTEM

摘要

SO1077 AUTOMATIC TRACKING SERVO CONTROL SYSTEM An automatic tracking servo control system which is adapted to control the tracking of at least one rotary signal reproducing head which scans successive-parallel record tracks on a movable record medium. Position pulses are generated when the at least one head rotates into predetermined position with respect to the record medium, and these position pulses are used in conjunction with control signals which are reproduced from the record medium and which had been recorded at spaced locations therealong in predetermined relation to the record tracks for controlling the position of the at least one head with respect to the tracks scanned thereby. A detector detects the relative strength of the signal reproduced by the at least one head during periodic intervals. A phase shift circuit shifts the phase of each reproduced control signal as a function of the difference between the relative signal strengths in successive periodic intervals. The phase-shifted control signal is used in a servo circuit, together with the position pulses, to control the tracking of the rotary head. -i-