| 摘要 |
PURPOSE:To improve the increase in secondary distortion, by providing an erasing head having wider track width than the track pitch and flowing an AC current having a DC offset or a DC current to the erasing head. CONSTITUTION:Where the direCtion of windings on a head core is the same, the case is taken as (a) and where different, it is taken as (b). In the case of (a), a DC current is applied reversingly as shown in the arrows to obtain inverse direction of magnetic flux generated with each other. In case of (b), the DC current is applied in the same direction and the direction of windings is taken opposite to each other to generate magnetic flux of opposite directions. When the width TW of a recording track is narrower than a track pitch TP, a guard band of TP-TW is caused. Although the guard band is subjected to the DC erasing magnetic field at DC erasing and the entire magnetization is saturated unidirectionally, since the direction of magnetization for each track is opposite, the effect of the gurad band at reproduction is cancelled. Thus, a picture with less secondary distortion can be achieved. |
