公开(公告)号：WO1989000330A1

公开(公告)日：1989-01-12

申请号：PCT/JP1988000679

申请日：1988-07-06

Applicant: KABUSHIKI KAISHA C S K ,  HORIE, Kiyoshi

Inventor： KABUSHIKI KAISHA C S K

IPC: G11B20/16

CPC classification number: G11B20/16

Abstract: A circuit for reading from an optical recording medium having a clock track which is provided in parallel with data tracks and holds recorded clock bits forming a predetermined optical pattern. A reader circuit reads a clock track which contains a series of regularly arranged clock bits and some irregular clock bits that disturb the regularity of the former clock bits. This circuit includes a phase-locked loop (PLL) circuit for receiving the clock signal read from the clock track, and irregular clock detecting means for comparing the clock output of the PLL circuit with the read signal to generate a detect pulse when the disturbing irregular clock bit is detected. Even if the PLL circuit gets unlocked temporarily, the head word is recognized according to irregular clock bits provided in the clock track when the PLL circuit returns to the locked condition. Therefore, the data which are read subsequently can be properly recognized. Further, the invention can be realized without decreasing the recording capacity of the optical recording medium.

公开(公告)号：WO1989000329A1

公开(公告)日：1989-01-12

申请号：PCT/JP1988000678

申请日：1988-07-06

Applicant: KABUSHIKI KAISHA C S K ,  HORIE, Kiyoshi

Inventor： KABUSHIKI KAISHA C S K

IPC: G11B20/12

CPC classification number: G11B20/16

Abstract: An optical recording medium having a clock track is provided in parallel with data tracks and holds recorded clock bits forming a predetermined optical pattern. In an optical recording medium having a clock track and a data track, the clock track contains a series of regularly arranged clock bits and some irregular clock bits that disturb the regularity of the former clock bits. Even if the PLL circuit gets unlocked temporarily, the head word is recognized according to irregular clock bits provided in the clock track when the PLL circuit returns to the locked condition. Therefore, the data which are read subsequently can be properly recognized. Further, the invention can be realized without decreasing the recording capacity of the optical recording medium.