Method of converting a stream of databits of a binary information signal into a stream of databits of a constrained binary channel signal, device for encoding, signal comprising a stream of databits of a constrained binary channel signal, record carrier, method for decoding, device for decoding

A device for encoding a stream of databits of a binary information signal into a stream of databits of a constrained binary channel signal, said binary information signal comprising n-bit information words, said binary channel signal comprising a sequence of channel words, said sequence of channel words comprising m1-bit channel words and m2-bit channel words, the device comprising:

• an n-to-m1-bit converter for converting the n-bit information words into corresponding m1-bit channel words,
• an n-to-m2-bit converter for converting the n-bit information words into corresponding 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,
• wherein the n-to-m1 bit converter is additionally arranged to select the m1-bit channel word depending on an end part of the preceding channel word in said sequence of channel words,
• wherein the n-to-m2 bit converter is additionally arranged to select the m2-bit channel word depending on an end part of the preceding channel word in said sequence of channel words,
• wherein n, m1, and m2 are positive integers such that m2>m1>n,
• wherein at least two of said m2-bit channel words have opposite parities,
• wherein said channel words are concatenated such that said sequence of channel words comprises said concatenated channel words,
• wherein said concatenated channel words comprise concatenated m1-bit channel words and m2-bit channel words,
• wherein said concatenated m1-bit channel words and m2-bit channel words comply with a runlength constraint of the binary channel signal,
• wherein each m1-bit channel word is associated with a coding state of a channel code C1, said coding state of said channel code C1 being established in dependence upon an end part of the preceding channel word in said sequence of channel words,
• wherein each m2-bit channel word is associated with a coding state of a channel code C2, said coding state of said channel code C2 being established in dependence upon an end part of the preceding channel word in said sequence of channel words, and
• wherein end parts of the m1-bit channel words in a coding state of channel code C1 and beginning parts of the m2-bit channel words in a coding state of channel code C2 are arranged to comply with said runlength constraint, and
• wherein at least one of the n-to-m1-bit converter and the n-to-m2-bit converter comprises substitution means for substituting a limited number of channel words for substitute channel words so as to influence predetermined properties of the binary channel signal, the substituted channel word and the substitute channel word establishing the same state.

A constrained binary channel signal comprising a sequence of channel words:

• wherein each said channel word is selected from the group consisting of an m1-bit channel word in accordance with a channel code C1 and an m2-bit channel word in accordance with a channel code C2,
• wherein m1 and m2 are positive integers such that m2>m1,
• wherein at least two of said m2-bit channel words have opposite parities,
• wherein said channel words are concatenated such that said sequence of channel words comprises said concatenated channel words,
• wherein said concatenated channel words comprise concatenated m1-bit channel words and M2-bit channel words,
• wherein said concatenated m1-bit channel words and m2-bit channel words comply with a runlength constraint of the binary channel signal,
• wherein each m1-bit channel word is associated with a coding state of said channel code C1, said coding state of said channel code C1 being established in dependence upon an end part of the preceding channel word in said sequence of channel words,
• wherein each m2-bit channel word is associated with a coding state of said channel code C2, said coding state of said channel code C2 being established in dependence upon an end part of the preceding channel word in said sequence of channel words,
• wherein end parts of the m1-bit channel words in a coding state of channel code C1 and beginning parts of the m2-bit channel words in a coding state of channel code C2 are arranged to comply with said runlength constraint, and
• wherein, in dependence upon a value of a predetermined property of the binary channel signal, a channel word substitutes for a substitute channel word so as to influence the value of the predetermined property of the binary channel signal, wherein the substituted channel word and the substitute channel word establish a same state.

A record carrier, comprising tracks having an information pattern recorded therein:

• wherein the information pattern represents a portion of a constrained binary channel signal,
• wherein the information pattern comprises first parts and second parts alternating in the direction of a track of said tracks,
• wherein the first parts represent first bit cells of the binary channel signal such that the first bit cells have a low signal level,
• wherein the second parts represent first bit cells of the binary channel signal such that the first bit cells have a high signal level,
• wherein the portion of the constrained binary channel signal comprises a sequence of channel words,
• wherein each said channel word is selected from the group consisting of an m1-bit channel word in accordance with a channel code C1 and an m2-bit channel word in accordance with a channel code C2,
• wherein m1 and m2 are positive integers such that m2>m1,
• wherein at least two of said m2-bit channel words have opposite parities,
• wherein said channel words are concatenated such that said sequence of channel words comprises said concatenated channel words,
• wherein said concatenated channel words comprise concatenated m1-bit channel words and m2-bit channel words,
• wherein said concatenated m1-bit channel words and m2-bit channel words comply with a runlength constraint of the binary channel signal,
• wherein each m1-bit channel word is associated with a coding state of said channel code C1, said coding state of said channel code C1 being established in dependence upon an end part of the preceding channel word in said sequence of channel words,
• wherein each m2-bit channel word is associated with a coding state of said channel code C2, said coding state of said channel code C2 being established in dependence upon an end part of the preceding channel word in said sequence of channel words,
• wherein end parts of the m1-bit channel words in a coding state of channel code C1 and beginning parts of the m2-bit channel words in a coding state of channel code C2 are arranged to comply with said runlength constraint, and.
• wherein, in dependence upon a value of a predetermined property of the binary channel signal, a channel word substitutes for a substitute channel word so as to influence the value of the predetermined property of the binary channel signal, wherein the substituted channel word and the substitute channel word establish a same state.

A method of decoding a stream of databits of a constrained binary channel signal into a stream of databits of a binary information signal that includes n-bit information words, the method comprising converting the constrained binary channel signal into the binary information signal:

• wherein the binary information signal includes a sequence of channel words,
• wherein one of said n-bit information words is generated from each of said channel words,
• wherein each said channel word is selected from the group consisting of an m1-bit channel word in accordance with a channel code C1 and an m2-bit channel word in accordance with a channel code C2,
• wherein m1 and m2 are positive integers such that m2>m1,
• wherein at least two of said m2-bit channel words have opposite parities,
• wherein said channel words are concatenated such that said sequence of channel words comprises said concatenated channel words,
• wherein said concatenated channel words comprise concatenated m1-bit channel words and m2-bit channel words,
• wherein said concatenated m1-bit channel words and m2-bit channel words comply with a runlength constraint of the binary channel signal,
• wherein each m1-bit channel word is associated with a coding state of said channel code C1, said coding state of said channel code C1 being established in dependence upon an end part of the preceding channel word in said sequence of channel words,
• wherein each m2-bit channel word is associated with a coding state of said channel code C2, said coding state of said channel code C2 being established in dependence upon an end part of the preceding channel word in said sequence of channel words,
• wherein end parts of the m1-bit channel words in a coding state of channel code C1 and beginning parts of the m2-bit channel words in a coding state of channel code C2 are arranged to comply with said runlength constraint,
• wherein, in dependence upon a value of a predetermined property of the binary channel signal, a channel word substitutes for a substitute channel word so as to influence the value of the predetermined property of the binary channel signal, wherein the substituted channel word and the substitute channel word establish a same state, and
• wherein, during said converting, one n-bit information word is assigned to one channel word or to one substitute channel word.

A device for decoding a stream of databits of a constrained binary channel signal into a stream of databits of a binary information signal that includes n-bit information words, the device comprising converting means for converting the constrained binary channel signal into the binary information signal:

• wherein the binary information signal includes a sequence of channel words,
• wherein one of said n-bit information words is generated from each of said channel words,
• wherein each said channel word is selected from the group consisting of an m1-bit channel word in accordance with a channel code C1 and an m2-bit channel word in accordance with a channel code C2,
• wherein m1 and m2 are positive integers such that m2>m1,
• wherein at least two of said m2-bit channel words have opposite parities,
• wherein said channel words are concatenated such that said sequence of channel words comprises said concatenated channel words,
• wherein said concatenated channel words comprise concatenated m1-bit channel words and m2-bit channel words,
• wherein said concatenated m1-bit channel words and m2-bit channel words comply with a runlength constraint of the binary channel signal,
• wherein each m1-bit channel word is associated with a coding state of said channel code C1, said coding state of said channel code C1 being established in dependence upon an end part of the preceding channel word in said sequence of channel words,
• wherein each m2-bit channel word is associated with a coding state of said channel code C2, said coding state of said channel code C2 being established in dependence upon an end part of the preceding channel word in said sequence of channel words,
• wherein end parts of the m1-bit channel words in a coding state of channel code C1 and beginning parts of the m2-bit channel words in a coding state of channel code C2 are arranged to comply with said runlength constraint,
• wherein, in dependence upon a value of a predetermined property of the binary channel signal, a channel word substitutes for a substitute channel word so as to influence the value of the predetermined property of the binary channel signal, wherein the substituted channel word and the substitute channel word establish a same state, and
• wherein said converting means converts one n-bit information word to one channel word or to one substitute channel word.

A method of converting a stream of databits of a binary information signal into a stream of databits of a constrained binary channel signal, the method comprising:

• converting each n-bit information word of a binary information signal into a channel word such that the binary channel signal includes a sequence of channel words;
• and
• substituting, in dependence upon a value of a predetermined property of the binary channel signal, a substituted channel word for a substitute channel word so as to influence the value of the predetermined property of the binary channel signal, wherein the substituted channel word and the substitute channel word establish a same state:
• wherein each said channel word is selected from the group consisting of an m1-bit channel word in accordance with a channel code C1 and an m2-bit channel word in accordance with a channel code C2,
• wherein n, m1, and m2 are positive integers such that m2>m1>n.

A device for encoding a stream of databits of a binary information signal [ into a stream of databits of a constrained binary channel signal, said binary information signal comprising n-bit information words, said binary channel signal comprising a sequence of channel words, said sequence of channel words comprising m1-bit channel words and m2-bit channel words, the device comprising:

• an n-to-m1-bit converter for converting the n-bit information words into corresponding m1-bit channel words,
• an n-to-m2-bit converter for converting the n-bit information words into corresponding 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,
• wherein n, m1, and m2 are positive integers such that m2>m1>n, and
• wherein at least one of the n-to-m1-bit converter and the n-to-m2-bit converter comprises substitution means for substituting a limited number of substituted channel words for substitute channel words so as to influence predetermined properties of the binary channel signal, the substituted channel word and the substitute channel word establishing the same state.