| 摘要 |
PURPOSE:To make the reading speed of information of a rotary head constant independently of the change in the running speed of a magnetic tape by changing the head speed of the rotary head in matching with the running speed of the magnetic tape. CONSTITUTION:When a magnetic tape T is run at a constant speed, a signal is reproduced by a rotary head 1, and a frequency of a clock signal extracted by a PLL circuit 5 extracted from a reproducing signal extracted by a rotary head 1 and reaching the PLL circuit 5 via a head amplifier 2, an equalizer circuit 3 and a waveform shaping circuit 4 is matched with the frequency of a reference clock signal outputted from a reference clock signal generating circuit 7. Thus, a frequency error signal outputted from a frequency comparison circuit 8 is shown by zero and also the output of an error signal generating circuit 9 is shown by zero, resulting that a drum motor control circuit 10 drives a drum motor 11 at a constant speed to read information from a recording track TR at a prescribed rate in the relation of a head speed Vh of the rotary head 1, the reading speed VR by the rotary head 1 with respect to the tape speed Vt.
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