| 摘要 |
PURPOSE:To reverse tape running as soon as a magnetic tape end comes to a head without being affected by external light by using a head to detect a level difference of hiss noise between a magnetic tape and a leader tape part to discriminate the end of the magnetic tape. CONSTITUTION:A hiss noise detection section uses a high-pass filter 5 to extract the hiss noise component only and when the hiss noise exceeds a prescribed level, an output of a comparator 6 goes to a high level and a low level is outputted when the noise level is a prescribed level or below. That is, when the magnetic tape is running, since the hiss noise level is high, the output of the comparator 6 goes to a high level, a transistor (TR) 7 is turned off, a plunger 8 is not operated and the tape running direction is continued. When the leader tape or cleaning tape is running, the output of the comparator 6 goes to a low level and the TR 7 is turned on. Thus, the plunger 8 is operated, the tape running is inverted to attain quick reversing.
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