| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical disk capable of reproducing correct digital data by performing the detecting of synchronization and the reproducing of clocks surely at the time of reproducing the disk while using a pit edge multi-valued recording system and an optical disk reproducer. SOLUTION: A data area 1a carrying digital data and a servo area 1b to be the reference of a servo control are alternatingly formed on an optical disk 1. On a data pit Pd in the data area 1a, ternary digital data are recorded at respective pit edges by the pit edge multivalued recording sytstem and the center value of a pit length is set to L and the pit cycle is set to 2L along a recording track and data pits Pd are alternately arranged so as become reverse phases with each other between adjacent tracks. On the other hand, the pit length of a synchronous pit Ps in the servo area 16 is set to 2L and synchronous pits Ps are arranged forming a line at the same positions of a track direction between adjacent tracks. Consequently, the levels of sampled values corresponding to the synchronous pits Ps are made large and made to be the reference for detecting the synchronization. Moreover, the frequency control and the phase control of reproducing clocks can be performed and also the DC level of the series of sampled values can be corrected based on the synchronous pits Ps.
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