JPS6449486A - Rolling correcting circuit - Google Patents

Abstract

PURPOSE:To execute a rolling correction to such an extent that a lock is not released and to obtain an easy-to-see reproducing image by preparing the pulse width or amplitude of a rolling correcting pulse so as to make smaller than a prescribed value for a prescribed period after a migration from another repro ducing condition to an intermittent slow reproducing condition. CONSTITUTION:When a video tape recorder is set from a normal reproducing condition to the intermittent slow reproducing condition, the same instruction is issued also to a servo IC3 and a microcomputer 2, and the rotating speed reference of a cylinder motor is changed at the IC3. A computer 2 inputs a head switching signal RFSW, makes the width of a rolling correcting pulse (a) into a small value until the activation of a capstan motor exceeds a pre scribed value based on a cylinder FG signal HFG and a capstan FG signal CFG, and prevents the phase lock of a cylinder servo from being prevented. When a locking condition is approximately made, a control is executed so that the width of the pulse (a) an be gradually increased and go up to the prescribed value. In such a way, the easy-to-see reproducing image can be obtained by executing the rolling correction to such an extent that the lock is not released.