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AssigneeKoninklijke Philips Electronics N.V.
InventorKornelis Antonie Schouhamer Immink
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This invention relates to a digital modulation method and apparatus used for recording an audio or video signal, computer data, and etc on a recording medium such as an optical or magneto-optical disc. Data words of m bits are translated into code words of n bits in accordance with a conversion table. The code words satisfy a (d, k) constraint in which at least d “0”s and not more than k “0”s occur between consecutive “1”s. The n-bit code words alternate with p-bit merging words which are selected such that between the leading “1” in the code word following the merging word and the trailing “1” in the merging word are at least d “0”s, and further that between the trailing “1” in the code word preceding the merging word and the leading “1” in the merging word are at least d “0”s. The merging word that satisfies said conditions, yielding the lowest dc imbalance of the modulated signal obtained after modulo-2 integration of the catenation of the alternate code words and merging words is selected. Then, the modulated signal is generated by the catenation of alternate code words and merging words integrated modulo-2 in which a “1” becomes a transition and a “0” becomes an absence of a transition. A unique synchronizing word is inserted periodically.
A method of coding a sequence of binary data bits into a sequence of binary channel bits, wherein consecutive and sequential blocks of m data bits, where m an integer, are coded into sequential n-bit code words, where n an integer exceeding m, in accordance with a translation table, wherein the code words satisfy a dk-constraint such that consecutive “1”s are separated by at least d and at most k “0”s, and where between said consecutive code words a p-bit merging word, where p an integer, is inserted, the catenation of said alternate code words and merging words satisfying the conditions that between the leading “1” in the merging word and the trailing “1” in the code word preceding the merging word are at least d “0”s, and that between the trailing “1” in the merging word and the leading “1” in the code word following the merging word are at least d “0”s, characterized in that the merging words are not required to obey said d constraint.
Dependencies are inferred from the claim text.