| 摘要 |
PURPOSE:To improve an S/N without being affected adversely by picked up noise from an erasure core even if a track shift arises by providing the erasure core with an additional one, or adding a transformer circuit to the erase coil of the erasure core and connecting it to the reproduction coil of a recording and reproducing core. CONSTITUTION:The additional coil 10 is inserted into the erasure core 4 separate from the erasure coil 6. A signal VE' having the same amplitude as that of a VE with a reverse phase of 180 deg. of the waveform of the signal VE is read out of the additional coil 10, which is connected to a recording and reproducing coil 3. Then each signal is added to offset the waveform of the amplitude VE, and the S/N is improved. In terms of the winding direction of the additional coil 10, the flux direction of a broken line interlinking the additional coil 10 with the flux picked up from an erasure core hollow 8 is opposite to that of an alternate long and short dash line interlinking the recording and reproduction coil 3. When the winding direction of the additional coil 10 is equal to that of the recording and reproducing coil 3, the waveform VE' different in phase from the VE by 180 deg. can be obtained.
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