| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical information recording and playback method and device for further improving density by reducing influence on playback signal level detection due to a low frequency component noise contained in a playback signal to enhance accuracy of the playback signal level detection. SOLUTION: In the optical information recording and playback device, cells are virtually provided at fixed intervals on an information track of an optical information medium recording and playback information using an optical spot, information pits are recorded for every cell according to a recording level of a predetermined ternary or more value and recorded information is reproduced by detecting a playback signal level of multi steps from the information pits at playback. In the optical information recording and playback device, a cell central value corresponding to the playback signal level at the time when the center of the optical spot is aligned with the center of the cell on the information track is detected, difference of detected two cell central values is calculated and recorded information is reproduced using the calculated difference value. COPYRIGHT: (C)2009,JPO&INPIT
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