Data decoder

Abstract

The level of a reproduced RF signal (7a) is temporarily stored in an RF signal level storage (20) when the binary level of a channel bit is judged. The part of a channel bit data train which does not satisfy the conditions of a minimum continuous length and a maximum continuous length of the same symbol is detected by a (d'-1) detector (16) and a (k'+1) detector (17). The decoder is provided with position detectors (18, 19) adapted to output corrected bit positions designating signals on the basis of the level of the RF signal stored in the RF signal level storage (20) when a binary level is judged, and a bit data reversing and correcting element (15) adapted to reverse the logical level of a position of a bit designated on the basis of corrected bit position designating signals (18a, 18b, 19a, 19b). When channel bit data obtained by binarizing a signal read out from a recording medium include a part which does not satisfy the conditions of a minimum continuous length and a maximum continuous length of the same symbol, a bit error rate can be improved by making corrections on the channel bit data, and this also enables a skew marging to be secured.

Description

Technical field [0001] The present invention relates to a data decoder adapted to use RLL (Limited Run Length) to encode a reproduced RF signal read from a recording medium on which information is recorded to output channel bit data according to at least one comparison level, in particular to A data decoder, when there is any part in the channel comparison signal that does not satisfy the minimum run length and maximum run length conditions of the same symbol, it is considered to be an error when the level discrimination is performed based on the RF signal level. The high probability bits of the code are used to correct the selected bits, thereby outputting channel bit data that meets the minimum run length and maximum run length conditions of the same symbol. Background technique [0002] When transmitting data or recording data on a recording medium such as a magnetic disk, an optical disk, or a magneto-optical disk, etc., data modulation is performed to make it consistent with...

AI Technical Summary

Problems solved by technology

[0014] The object of the present invention is to solve the above-mentioned problem, and its object is to provide a kind of data decoding apparatus, this data decoding apparatus is suitable for the channel bit data obtained by binarizing the signal read out from the recording medium. In the case of the minimum run length and the part of the maximum run length condition of the symbol, correction is performed on the channel bit data to output the channel bit data satisfying the maximum run length and the minimum run length condition of the same symbol, thus it is possible to improve the bit error rate, and make sure to skew the bounds

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