| 摘要 |
<p>Apparatus for controlling the speed of advancement of tape extending between supply and take-up reels in a VTR during changes in the speed of advancement of the tape includes for each reel a tape radius detector which detects the radius of the tape on the respective reel from the center of the reel hub to the outer loop of tape; acceleration detector which detects the acceleration or deceleration of the tape during such changes in speed; a tape tension detector which detects the tension of the tape adjacent the respective reel; a torque detector which detects the torque imparted to the respective reel by a respective drive motor at the start of the speed change; a circuit which produces a total moment of inertia signal corresponding to the total moment of inertia of the respective reel with the tape wound thereabout, in response to the detected radius, acceleration, tape tension, and torque; a torque calculating circuit which produces a torque signal corresponding to a desired torque necessary to maintain the acceleration or deceleration of the tape at a substantially constant value, in response to the detected radius, acceleration, and tape tension and the total moment of inertia signal; and a current control circuit which controls the current supplied to the respective drive motor in response to the torque signal so that the drive motor imparts a torque to the respective reel to maintain the acceleration or deceleration substantially constant.</p> |
