PURPOSE:To decrease the hardware quantity of error correction and detection by executing simultaneously a syndrom calculation and a CRC checking calculation and correcting a CRC checking result with a syndrom calculation result. CONSTITUTION:Reading data 1 read from a driving device 25 pass through a demodulating circuit 18 and are sent to a data selecting circuit 21, a CRC checking circuit 19 and a syndrom calculation circuit 20 as demodulating data 2. The CRC checking calculation and the syndrom calculation are simultaneously executed and when the error is corrected, by a syndrom calculation result 17, it is necessary to correct a CRC checking result 16 executed by the data before the correction, and the correcting value is computed by a micro program 23 from a corrected position and pattern. Thus,the syndrom calculation and the CRC checking can be simultaneously executed, a hard constitution can be simplified and the hardware quantity can be reduced.
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