| 摘要 |
PROBLEM TO BE SOLVED: To improve accuracy of iterative decoding in a magnetic recording and reproducing device of helical-scan system, which can perform processing by using an estimated value of variance near a right value from immediately after scan start by a reproducing head. SOLUTION: A maximum value in estimated values of variance held in a variance estimated value register within a given time period from scan start is held in a maximum value hold register 38. When starting next scan, the maximum value held in the maximum value hold register 38 in starting the last time scan is set to a variance estimated value register 37. Accordingly, computing of a logarithm likelihood ratio can be performed by an estimated value of variance near the right value from immediately after the scan start, and the accuracy of iterative decoding can be improved. COPYRIGHT: (C)2009,JPO&INPIT
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