SERVO CONTROL METHOD WITHOUT TAPE CONTROL SIGNAL

摘要

A method preserves a proper picture on a screen when the control pulse to control the velocity and the phase of a capstan motor is not found. The method comprises the steps of: detecting that the control pulse is not found; comparing the predetermined value (X) with the envelope value detected by controlling the velocity of the capstan motor; controlling the velocity of the capstan motor continuously if the envelope value is larger than the predetermined value, and performing the phase control routine without the control pulse if the envelope value is smaller than the predetermined value.