Development of Dynamic Drum Control System for VCR

Abstract

This paper describes a new control system for VCR drums. The system, called the Dynamic Drum (DD) system, has the drum assembly's rotation axis tilted to accurately trace recording tracks for noise-free playback. The tilt angle for each playback speed is coarsely controlled by a rotary encoder; the tilt angle is finely controlled by a detected envelope of playback signals. The 2-step control of the DD enables fast angle determination and high stability even for videotapes recorded on other VCRs. The data for the optimum tilt angle at each playback speed can be saved for coarse tilt angle control.