| 摘要 |
PURPOSE:To remove a useless data reading time by executing parity check only in a series having no error pointer. CONSTITUTION:At the execution of parity check, error correction is executed only for a series having one error pointer and parity check is executed only for a series having no error pointer. A detecting circuit 6 is turned on by a detection control circuit 14 in the 1st and 4th 123 series reading periods and a switch 9 is turned by the detecting circuits 6, 5 in accordance with the number of error pointers, i.e. '1' or '0', to execute parity check and error correction. In other periods, e.g. the 2nd, 3rd and 5th periods, the detecting circuit 6 is turned off and the switch 9 is turned to the contact (b) side to repeat the correction of the P and Q series alternately.
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