device for control of bandrorelsen at a stegande magnetbandtransport

摘要

In a rotating head magnetic tape transport, the tape is maintained stationary as the head sweeps a selected data track. A length of tape is buffered in a vacuum column between a supply spool and the rotating head station. A take-up spool on the opposite side of the head station is servo controlled to maintain proper head/track alignment and to periodically step the tape to an adjacent track. Changes in the tape radius on the take-up spool are compensated for by (1) a stop-lock source of motor energization whose magnitude is servo controlled by unbalance between the vacuum column force tending to pull the tape in one direction and the take-up spool motor torque tending to pull the tape in the opposite direction, and (2) a step modification network which responds to head/track alignment error caused by the variable tape radius on the take-up spool.