| 摘要 |
PURPOSE:To attain the demodulation and the error detection with a simple circuit constitution by detecting whether or not the pattern of '101' is included in the bit pattern of 15 bits when an optical disk is reproduced in which the data are demodulated to 4/15 and recorded. CONSTITUTION:In an magneto optical disk 1, 4/15-modulated data are recorded. By a differential detection means 10, the data of the high level out of reproducing RF signal data are detected, and the position of the reproducing RF signal data with the high level is obtained. Thus, the data recorded in the magneto optical disk 1 are reproduced. The reproduced data is given to a 14-8 converting means 11 and the demodulation of the 4/15 modulation is executed. The data returned to the data of 8 bits are sent to an error correcting means 12 by the 14-8 converting means 11, and after the error correction is executed, the data are sent from an output terminal 13. For the error detection, it is detected whether or not the pattern of '101' appears in the pattern of reproducing data. By the 4/15-modulation, it can be remarked that the error is included in the reproducing data from a modulation rule. Thus, by detecting the error and demodulating the error, the error cannot be overlooked even when the circuit scale is reduced.
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