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AssigneeKoninklijke Philips Electronics N.V.
InventorWillem Marie Julia Marcel Coene
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The invention relates to a method of converting a stream of databits of a binary information signal into a stream of databits of a constrained binary channel signal. This stream of databits of the binary information signal is divided into n-bit information words. These information words are converted into m1-bit channel words, in accordance with a channel code C1, or m2-bit channel words, in accordance with a channel code C2, where m1, m2 and n are integers for which it holds that m2>m1≧n. The m2-bit channel word is chosen from of at least two m2-bit channel words, at least two of which have opposite parities, the concatenated m1-bit channel words and the m2-bit channel words complying with a runlength constraint of the binary channel signal. The method comprises the repetitive and/or alternate steps of: selecting the m1-bit channel word from a set out of a plurality of sets of m1-bit channel words, each set comprising only m1-bit channel words having a beginning part out of a subset of beginning parts of the m1-bit channel words, each set being associated with a coding state of channel code C1, the coding state being established in dependence upon an end part of the preceding channel word, or: selecting the m2-bit channel word from a set out of a plurality of sets of m2-bit channel words, which selection depends on the end part of the preceding channel word, each set comprising only m2-bit channel words having a beginning part out of a subset of beginning parts of the m2-bit channel words belonging to said set, each set being associated with a coding state of channel code C2, the coding state being established in dependence upon an end part of the preceding channel word. The end parts of the m1-bit channel words in a coding state of channel code C1 and the beginning parts of the m2-bit channel words in a set of channel code C2 are arranged to comply with said runlength constraint. The invention further relates to a device for encoding, a signal comprising a stream of databits of a constrained binary channel signal, a record carrier and a device for decoding.
A method of converting a stream of databits of a binary information signal into a stream of databits of a constrained binary channel signal, wherein the stream of databits of the binary information signal is divided into n-bit information words, said information words being converted into m1-bit channel words in accordance with a channel code C1, or m2-bit channel words, in accordance with a channel code C2, where m1, m2 and n are integers for which it holds that m2>m1≧n, wherein the m2-bit channel word is chosen from at least two m2-bit channel words, at least two of which have opposite parities, the concatenated m1-bit channel words and the m2-bit channel words complying with a runlength constraint of the binary channel signal,
A device for encoding a stream of databits of a binary information signal into a stream of databits of a constrained binary channel signal, for performing one of the methods as claimed, the device comprising an n-to-m1-bit converter for converting the n-bit information words into m1-bit channel words, an n-to-m2-bit converter for converting the n-bit information words into m2-bit channel words, state-establishing means for establishing a coding state of the m1-bit channel words and of the m2-bit channel words, which n-to-m1 bit converter is further arranged for selecting the m1-bit channel word depending on the end part of the preceding channel word, which n-to-m2 bit converter is further arranged for selecting the m2-bit channel word depending on the end part of the preceding channel word.
A signal comprising a stream of databits of a constrained binary channel signal, obtained after carrying out one of the methods as claimed.
A record carrier on which the signal as claimed is recorded in a track, in which information patterns represent the signal portions, which information patterns comprise first and second parts, alternating in the direction of the track, the first parts presenting detectable properties and the second parts presenting detectable properties which are distinguishable from the first properties, the parts having the first properties representing bit cells having the first logic value and the parts having the second properties representing the bit cells having the second logic value.
A device for decoding a stream of databits of a constrained binary channel signal into a stream of databits of a binary information signal, the device comprising converting means for converting the signal as claimed into a bit string of bits having a first or a second value, the signal containing the m1-bit channel words and the m2-bit channel words, the bit string comprising the n-bit information words, the converting means being arranged to convert the m1-bit channel words and m2-bit channel words into n-bit information words, wherein one information word is assigned to one channel word to be converted.
Dependencies are inferred from the claim text.