CONTROLLER OF MAGNETIC TAPE RUNNING SPEED

摘要

PURPOSE:To stably control the running of a tape at the time of reproducing the magnetic tape by making the stationary phase deviation between the reproduced signal and a synchronized reference signal nearly zero. CONSTITUTION:At the time of reproduction, a speed control loop is constituted in such a manner that an FG reference period 31 is taken as the rotation reference value of a motor 4 until the change of the phase difference per a specified time between the reproduced signal and the synchronized reference signal 32 becomes a prescribed value by a phase change detecting circuit 18. By constituting the speed control loop with an average value of the rotation period of the motor 4 held by a latch circuit 8 as the rotation reference value of the motor 4, when this change becomes smaller than the prescribed value, the stationary phase deviation between the reproduced signal and the synchronized reference signal 32 is made nearly zero even in the case the difference between the tape running speed at the time of recording and the tape running speed in this speed control loop is large.