| 摘要 |
<p>In a magnetic disk apparatus, a magnetic disk has a plurality of servo sectors. Coarse and fine position data as servo data for positioning a magnetic head are recorded on each servo sector. The coarse position data is constituted by bit cells for identifying each data track and arranged in a track direction. Each bit cell represents a first or second value. Flux change occurs only at a boundary portion of a bit cell. Flux change occurs at leading edges of bit cells for every other bit in the same direction. Flux change does not occur at a central portion of a bit cell representing the first value, but occurs at a central portion of a bit cell representing the second value. Flux change occurs at the central portion of the bit cell in a direction opposite to that of flux change at the leading edge of a bit cell. The fine position data is constituted by two types of data respectively recorded at positions deviated from a central line of each data track toward the center of the disk and deviated toward the outer periphery of the disk such that a manner that a difference in amplitude between read signals serves as a function of a small positional deviation. <IMAGE></p> |
