| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical information recording and reproducing device for accurately detecting a level and exactly demodulating a multi-valued mark in multi-value recording. SOLUTION: The recording information signal of a binary code is multi- valued by a simple quaternary recording code table and a level signal to become a reference is generated on the basis of a portion, where the recording mark is not formed. Besides, the multi-valued recording information signal is binarized by a slice level signal and by ORing m-th and (m+1)th binarized recording information signals from the high order of (n-1) pit levels, a demodulated signal is generated.
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