In-cassette tape tensioning apparatus

Abstract

Apparatus for tensioning tape extending between two reels in a tape transport system having servos for controlling the velocity and position of the reels, includes position servo loop for maintaining the first reel in a fixed position. A velocity servo loop controls the other reel for taking up slack in the tape between the reels and applying a relative force on the tape once the slack has been taken up. The velocity servo is limited in the amount of current applied to the motor driving the take up reel by a signal provided by a tension servo connected to the position servo associated with the other reel. In particular, the tension servo responds to the amount of current applied by the position servo for applying a motor-current-limiting signal to the velocity servo system. When the position servo is applying minimal current to the fixed-position reel (when the tape is slack), a relatively large amount of current is allowed to go to the take up reel. As the tape becomes taut and the fixed-position reel is pulled out of position, the position servo applies increasing current to the motor in order to attempt to return the reel to the fixed position. The tension servo responds to the increasing current applied by the position servo, for reducing the amount of current applied to the take up reel motor.