| 摘要 |
PURPOSE:To detect a direction in operating access, by setting a distance between a pair on one side of wobble bits and a clock bit larger than a specified grade, and changing the distance repeatedly at every information track. CONSTITUTION:Bits 1-4 and a bit 5 constitute the pairs of wobble bits respectively, and the bit of every pair is deviated a little from the axes of track centers 7-10. The distance between the bits 1-4 and the bit 5 is deviated respectively. The distance between the bit 5 and the clock bit 6 of an information data is kept constant. The bit 6 becomes the clock reference of a recorded information data. The structure of a servo field is formed in cyclic structure of 16 tracks by continuing the same four tracks. Also, it is permitted to set the distances between the wobble bit and the clock bit in more than three grades instead of four grades. In such a way, it is possible to detect the direction in operating the access, and to improve the resolution of track count.
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