Method and apparatus for implementing maximum transition run codes
DC CAFCFirst Claim
1. Apparatus for encoding m-bit binary datawords into n-bit binary codewords, in a recorded waveform, where m and n are preselected positive integers such that n is greater than m, comprising:
- receiver means for receiving the dataword;
encoder means coupled to the receiver means, for producing sequences of fixed length codewords;
means for imposing a pair of constraints (j;
k) on the encoded waveform wherein the j constraint is defined as the maximum number of consecutive transitions allowed on consecutive clock periods in the encoded waveform to facilitate the reduction of a probability of a detection error in said receiver means;
said sequences generating no more than j consecutive transitions in the recorded waveform such that j is an integer equal to or greater than 2; and
said sequences generating no more than k consecutive sample periods without a transition in the recorded waveform.
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Abstract
Apparatus and method for coding to improve the minimum distance properties of sequence detectors operating at high densities in storage systems is presented. The coding scheme of the present invention is referred to as maximum transition run (MTR) code and eliminates data patterns producing long runs of consecutive transitions while imposing the usual k constraint necessary for timing recovery. The code has a distance gaining property similar to an existing (1,k) runlength-limited (RLL) code, but can be implemented with considerably higher code rates. When the MTR code is used with fixed delay tree search (FDTS) or high order partial response maximum likelihood (PRML) detectors, the bit error rate performance improves significantly over existing combinations of codes and detectors.
64 Citations
21 Claims
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1. Apparatus for encoding m-bit binary datawords into n-bit binary codewords, in a recorded waveform, where m and n are preselected positive integers such that n is greater than m, comprising:
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receiver means for receiving the dataword; encoder means coupled to the receiver means, for producing sequences of fixed length codewords; means for imposing a pair of constraints (j;
k) on the encoded waveform wherein the j constraint is defined as the maximum number of consecutive transitions allowed on consecutive clock periods in the encoded waveform to facilitate the reduction of a probability of a detection error in said receiver means;said sequences generating no more than j consecutive transitions in the recorded waveform such that j is an integer equal to or greater than 2; and said sequences generating no more than k consecutive sample periods without a transition in the recorded waveform. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for encoding m-bit binary datawords into n-bit binary codewords in a recorded waveform, where m and n are preselected positive integers such that n is greater than m, comprising the steps of:
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receiving binary datawords; and producing sequences of n-bit codewords; imposing a pair of constraints (j;
k) on the encoded waveform;generating no more than j consecutive transitions of said sequence in the recorded waveform such that j≧
2; andgenerating no more than k consecutive sample periods of said sequences without a transition in the recorded waveform. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21)
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Specification