| 摘要 |
PURPOSE:To track correctly a recording mark with a head and to obtain a satisfactory picture quality without a noise by forming a magnetic circuit part with a permanent magnet loaded to the moving part of an upper drum and a main coil and a sub-coil loaded at a lower drum. CONSTITUTION:A current (j) changing for one rotation of an upper drum 3 is passed through to main coil 41, a changed current (k) is pressed to a bus-coil 42, and whereby, two heads 5 are moved in a tape width direction by the same quantity only in the same direction to a magnetic tape. A current (l) is apparent ly increased by adding the current (k) to the current (j). Namely, to a displacing quantity in proportion to the current (j) of moving part 4a having a permanent magnet 49, the displacing quantity in proportion to the apparently increased current l to moving part 4a having a a permanent magnet 50 is coincident. Thus, the head 5 are moved under the control in a tape width direction, and the locus of the head at the time of a high speed research to start from a staring point at the time of the fixed head is bent from the starting point to the end point.
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