| 摘要 |
PURPOSE:To realize a low BER in the whole area of a recording area in an optical disk and to attain the recording of a large capacity of information by adopting a pit interval modulation PPM system for the inner peripheral part of the optical disk and a pit edge interval modulation PWM system for the outer peripheral part of the optical disk. CONSTITUTION:The optical disk is divided into four areas of a non-recording area 3, recording areas 4 and 5, and a non-recording area 6. The areas 4 and 5 except for the area 3 near a center hole 2 and the area 6 in the outer peripheral part are the recording areas. Digital signals are recorded by the PPM system for the recording area 4 on an inner side and by the PWM system for the recording area 5 on an outer side. Thus, the BER is low for the whole area of the recording area irrespective of the inner and outer peripheries of the optical disk, and a large capacity of information can be recorded. |
