| 摘要 |
PURPOSE:To obtain a small erasure signal remaining on a medium by forming the second gap at a position on the escape side of a magnetic recording medium, which is viewed from the gap and can obtain a magnetic field delayed by (2n+1)/2 periods from the phase of an AC magnetic field on the gap. CONSTITUTION:The second gap 6 is installed at the position where it deviates from the phase of the AC magnetic field on the 1st gap 5 by the (2n+1)/2 periods. Where the relative speed of the medium and the frequency of the AC erasure signal are (v) and (f), respectively, a magnetic layer 4 is spattered between the gaps 5 and 6 so as to satisfy x=[(2n+1)/2]Xv/f. With this constitution, the signal (f) remains as a small signal on the magnetic recording medium 7 after passing through a re-recording process caused by a reverse magnetic field with the aid of the small since wave of the signal (f) on the second gap 6, if the square wave of the signal (f) is applied from the gap 5. And a value when the erasure signal is picked up as a signal at the time of reproduction can be smaller by about 6 dB.
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