To improve an error correction capability without losing a high density recording effect as an optical disk device and also without prolonging a correction time like in the case of multiplexing error correction codes.
Among address data from a shift register 42, an error signal to a breach of 2-7 modulation rule is obtained from the address data not conforming to a code transformation rule of a demodulating ROM 44, and when every 5 bytes of data constitute 1 digit and an error signal of 3 bytes or more is generated for each digit, an error flag is outputted for the digit, and it is judged whether or not a re-sync code added to every 15 bytes is detected within a prescribed time, and if the re-sync code is not detected within the prescribed time, error flags are outputted to all the digits from the immediately preceding digit up to the one generating an error.
TAKAHASHI HIDEKI
YOSHIMARU TOMOHISA
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