| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical disk which secures a high C/N ratio and also simplifies the configuration of a demodulation circuit, too. SOLUTION: In this optical disk, the bit string of sub-information is divided by the unit of 4 bits (hexadecimal number) and recorded by the frequency modulation of wobble. That is, sub-information '0000' (0 h; h expresses hexadecimal number) is recorded by the wobble 16 period of a frequency F1 (period T1). Sub-information '0001' (1 h) is recorded by arranging the wobble 2 periods of a frequency F2 (period T2) and arranging the wobble 15 period of a frequency F1 after the wobble 2 periods. Subsequently, the same operation is performed. In this case, the frequency F2 is a frequency of F2=2×F1. This recording system records the sub information of 4 bits by the combination of the two-kinds of wobbles of the frequencies F1 and F2 and by the wobble of 16 T1 length. COPYRIGHT: (C)2004,JPO
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