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Modulation coding and decoding

A technology of modulation coding and coding, which is applied in the direction of code conversion, individual digital conversion, electrical components, etc., and can solve problems such as difficult to achieve

Inactive Publication Date: 2010-09-29
GLOBALFOUNDRIES INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

While this provides a practical implementation, the need for efficient Boolean logic for short block codes makes it difficult to achieve very high rates for the resulting PRML(G,I) codes

Method used

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  • Modulation coding and decoding
  • Modulation coding and decoding

Examples

Experimental program
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Embodiment Construction

[0058] figure 2 The block diagram of is a schematic representation of a data storage system embodying the invention, showing the main components involved in the recording / reproducing process. In this embodiment the data storage system is a tape drive (indicated generally at 1 ) and thus has a recording channel 2 with a read / write head 3 for reading and writing to a magnetic tape 4 . On the recording side, the tape drive 1 has modulation encoding means in the form of a PRML (G, I) encoder 5 , a precoder 6 and an ECC encoder generally indicated at 7 . The ECC encoder 7 includes an RS (Reed-Solomon) parity generator 8 and a partial interleaver 9 . On the reproduction side, the drive 1 comprises a detector arrangement, indicated generally at 11 and comprising a detector 12 and an ECC decoder 13 , together with a modulation decoder 14 .

[0059] In operation, the data to be recorded is provided to the PRML encoder 5 in the form of an input bitstream comprising a succession of M-...

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Abstract

Methods and apparatus are provided for modulation coding a stream of binary input data. A 4-ary enumerative encoding algorithm is applied to the input bit-stream to produce a succession of 4-ary output symbols. The 4-ary algorithm is operative to simultaneously encode respective generalized Fibonacci codes in the odd and even interleaves of the input bit-stream. The bits of each successive 4-ary output symbol are then interleaved, producing an output bit-stream which has global and interleaved run-length constraints. Inverting the bits of the 4-ary output symbols produces an output bit-stream with (G, I) -constraints as in the PRML (G, I) codes used in reverse-concatenation modulation systems. Corresponding decoding systems are also provided.

Description

technical field [0001] The present invention generally relates to methods and apparatus for modulation encoding input data and to corresponding modulation decoding systems. Background technique [0002] Modulation codes are used in data storage systems to eliminate undesirable bit sequences in recorded data, for example, bit sequences that cause errors during reproduction. One example of a bad bit sequence is a long string of bits with the same value. Another example is a long series of bits having the same value in alternate positions in the bitstream (ie, in odd (0) or even (E) interleaves (...EOEOEO...) of the bitstream. For example, long sequences of the form 0a0b0c0d0... (where a, b, c, etc. can be 0 or 1) will generally be bad. Modulation codes impose some form of constraint on the occurrence of undesirable bit sequences in the encoded bit stream. For example, some modulation codes impose a so-called j-constraint, whereby the maximum length of a consecutive series o...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H03M7/02
CPCH03M7/02H03M5/145H03M7/3088
Inventor T·米特尔霍尔泽
Owner GLOBALFOUNDRIES INC