| 摘要 |
An information recording and reproducing apparatus provided with the maximum likelihood decoding utilizes a standard deviation of difference metrics as an estimating function for adjustment for the purpose of achieving a short-time adjustment with a small number of samples. A regenerative clock and a reproduction signal outputted from the information recording and reproducing apparatus are supplied to a maximum likelihood decoder. Based on the estimated recorded series detected by the maximum likelihood decoder at a low error rate, a recording state detector generates a recorded bit series. Then, a standard deviation calculator operates to select a difference metric delayed by a detected amount by a display line from the difference metrics outputted from the maximum likelihood decoder and derives the standard deviation of the difference metrics. Then, a sigma - DELTA m/ mu - DELTA m minimizing controller operates to adjust a shift of a sampling phase and a track offset of the information recording and reproducing apparatus so that the standard deviation sigma - DELTA m is made minimal.
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