Abstract: A head switching signal generation apparatus for a VCR includes a pulse signal generator for generating a first pulse signal having the same phase and period of time as a head drum pulse signal in response to the head drum pulse signal, an envelope detector for detecting an envelope signal from a signal read out from a video tape and generating a second pulse signal having the same phase and period of time as the detected envelope signal, and a controller for generating a head switching signal whose pulse level is altered at an actual head switching point of time, based on the received first and second pulse signals. An accurate head switching signal can be generated even when a vertical sync signal is not detected from a video tape having a recording format for recording a vertical sync signal, as well as a recording format by which a vertical sync signal is not recorded on a video tape.

Abstract: A velocity control method for a rotary motor and an apparatus adopting the same estimates and corrects a disturbance applied to the rotary motor to improve a velocity control characteristic. The disturbance is expressed as a function of an angular velocity and an angular position via a simple calculation process. The velocity control apparatus includes a learning compensator for receiving a velocity command, angular position information and the output of a velocity controller and correcting an effect of the disturbance which is expressed as a function of the angular velocity and the angular position, in addition to a general velocity control loop of a rotary motor composed of a velocity controller, a current controller, a motor and a velocity measuring unit. The learning compensator stores one period of the output of the velocity controller at a steady state of the velocity control loop and obtains a correction value using the stored value and the previous output value.

Abstract: A servo apparatus for high speed reproduction in a digital video tape player includes heads and uses a helically scanned video tape on which high efficient coded video data is recorded in the same manner as being divisionally recorded at positions via which the head travels when intra-coded video data among the high efficient coded video data is reproduced at a high speed.