| 摘要 |
PURPOSE:To produce a servo signal of high accuracy and high quality by magnetizing previously the entire circumference of a magnetic disk in the same direction, flowing a current of a single direction to the winding of a magnetic head only at a position where the signal is written to invert the magnetizing direction of the disk and therefore producing a signal with the writing of one time and with no double writing. CONSTITUTION:''1'' is given as a write data signal to a signal position having the center of ''1'' to a head position 3, i.e., to signals CL and A, and the writing is carried out in accordance with the ''1''. Then the writing is carried out with a signal B to a head position 4 which is shifted by half pitch from the position 3. In the same way, the heads is shifted to a position 5 to perform the writing with signals CL and C. Then the head is shifted to a position 6 to carry out the writing with a signal D. Thus the writing is repeated while the head position is shifted toward the radius direction of a magnetic disk every half pitch of the track width. As a result, a double phase servo pattern is produced. In this case, only the magnetizing direction is inverted for a recording medium within a signal writing area, and no effect is given to other areas. Therefore no double writing is needed even in case an overlap pattern is desired. |
