Magnetic tape tension control - uses scanner for tension between pulling and pulled tape spools and control variable for adjusting braking or pulling action

摘要

When the tape transport, stops the control variable of the tape tension for the stopping period is stored in a memory, so that it is immediately available when the tape transport starts again. Or, when the tape transport resumes, the drive motor on the winding-on side is supplied with a brief run-up current pulse and the drive motor on the winding-off side is supplied with an adjustable braking current pulse smaller than the run-up current pulse. The tape tension desired for tape tension control results from the difference between the torques supplied by the two drive motors. In one embodiment, the light source is associated with a phototransistor and the output is connected through a memory element to the non-inverting input of an operational amplifier.