| 摘要 |
<p>PURPOSE:To output an inverting signal simply and surely, by operating a reproducing head even during recording, in a 3-head system tape recorder, and detecting the absence of a reproducing signal with a leader tape in contact with the reproducing head. CONSTITUTION:A tape 4 contacts an erasing head 3, recording head 2, and reproducing head 1 to form the recording mode. An output of the head 1 is amplified 5, band-passed 6, rectified 7, smoothed 8 and a voltage Vd1 is obtained. The voltage is compared with a reference voltage Es at a comparator 9, and when Vd1>Es, no output is obtained from the comparator. When the Es is set so that an output Vd2 is smaller than the Es in contact with the head 1 on the leader tape at the end of tape, the comparator 9 detects the tape end. At nonrecording, erased noise is inputted with the erasing head 3, and when the Es is set smaller than the reproduced output, no malfunction is produced. At the reproduction mode, the tape end can similarly be detected. Thus, the tape end can surely be detected.</p> |
