| 摘要 |
PROBLEM TO BE SOLVED: To perform high density recording, reproducing and rewriting by recording at every block adding a parity of a prescribed number to each row, each column of digital information and making it a product code, and re- encoding the block at a rewriting time of information and performing prescribed processing. SOLUTION: The parity of the prescribed number of symbols is added to the symbol data arranged in the row and column directions by a modulation circuit 14 to be made it the product code, and the whole is made one block, and an address is added to be recorded on a recording medium 1. In demodulating, a data control circuit 15 reads the signal of the specified block to store it in a buffer memory 16. An error correction circuit 17 repeats alternately the correction processing in the row and column directions until the error correction is ended. At the rewriting time of information, the whole block is read out similarly to the time at the demodulating time, and the error correction is performed to be rewritten in a sector unit by a recording means. Thus, an error correction rate is reduced, and a numerical aperture of an objective lens is enlarged, and the high density recording, reproducing and rewriting are performed. |
