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DC-free codes of rate (n-1)/n, n odd

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... Denote by ϑ 1 and ϑ 2 the lower and the upper bounds of this constrained range. The range of RDS bounded by ϑ 1 and ϑ 2 is said to be the digital sum variation (DSV), see [22], [23]. After the authors [23], DSV constrained RLL sequences are called DCRLL sequences. ...
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Constant-weight and constant-charge binary sequences with constrained run length of zeros are introduced. For these sequences, the weight and the charge distribution are found. Then, recurrent and direct formulas for calculating the number of these sequences are obtained. With considering these numbers of constant-weight and constant-charge RLL sequences as coefficients of convergent power series, generating functions are derived. The fact, that generating function for enumerating constant-charge RLL sequences does not have a closed form, is proved. Implementation of encoding and decoding procedures using Cover's enumerative scheme is shown. On the base of obtained results, some examples, such as enumeration of running-digital-sum (RDS) constrained RLL sequences or peak-shifts control capability are also provided.
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Preface to the Second Edition About five years after the publication of the first edition, it was felt that an update of this text would be inescapable as so many relevant publications, including patents and survey papers, have been published. The author's principal aim in writing the second edition is to add the newly published coding methods, and discuss them in the context of the prior art. As a result about 150 new references, including many patents and patent applications, most of them younger than five years old, have been added to the former list of references. Fortunately, the US Patent Office now follows the European Patent Office in publishing a patent application after eighteen months of its first application, and this policy clearly adds to the rapid access to this important part of the technical literature. I am grateful to many readers who have helped me to correct (clerical) errors in the first edition and also to those who brought new and exciting material to my attention. I have tried to correct every error that I found or was brought to my attention by attentive readers, and seriously tried to avoid introducing new errors in the Second Edition. China is becoming a major player in the art of constructing, designing, and basic research of electronic storage systems. A Chinese translation of the first edition has been published early 2004. The author is indebted to prof. Xu, Tsinghua University, Beijing, for taking the initiative for this Chinese version, and also to Mr. Zhijun Lei, Tsinghua University, for undertaking the arduous task of translating this book from English to Chinese. Clearly, this translation makes it possible that a billion more people will now have access to it. Kees A. Schouhamer Immink Rotterdam, November 2004
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A practical method for approaching the channel capacity of constrained channels
, "A practical method for approaching the channel capacity of constrained channels," IEEE Trans. Inform. Theory, vol. 43, pp. 1389-1399, 1997.