Patent ID: 6996048
Filing Date: 2006-02-07
Classification: G11B

Abstract:
1. A disk-like recording medium for concentrically recording auxiliary information of a disk in a second area other than a first area for recording contents data of said disk by a predetermined code, the recording medium comprising: n blocks, each block of said n blocks obtained by dividing said second area into n equal parts in a circumferential direction; and m frames, each frame of said m frames obtained by dividing said each block into m equal parts in the circumferential direction, wherein said auxiliary information is arranged in said frames in such a maimer as to be at equal intervals in the circumferential direction, and wherein said each frame includes a synchronization signal whose pattern is formed by arranging marks or spaces in three or more contiguous channel bits, such that said synchronization signal provides synchronism necessary for a playback apparatus to read said auxiliary information recorded in said second area, and wherein said auxiliary information is modulated by a 4-1 modulation method that modulates two data bits into seven channel bits.