US 7,119,721 B2 · Converting information words into different length code words depending on a property of a code signal

Abstract

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.

Claims49

Dependent claims

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, a concatenation of the m1-bit channel words and the m2-bit channel words complying with a runlength constraint of the binary channel signal, characterized in that 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, 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 being arranged to comply with said runlength constraint.

A method comprising:

receiving an information signal representing information words having n-bit values;
converting the information words into code words, some of the code words having m1-bit values and other of the code words having m2-bit values, m1, m2 and n are integers and m2>m1>n;
and
transmitting a code signal representing a sequence of code words, subsequent code words of the sequence immediately following preceding code words;
wherein:
the converting of information words into the corresponding m1-bit code words is in accordance with a conversion code C1;
the converting of information words into corresponding m2-bit code words is in accordance with a conversion code C2;
the sequence of code words complies with a runlength constraint and with a second constraint that is at least partially independent of the runlength constraint;
the converting includes selecting between conversion code C1 and conversion code C2 depending on a measure of the second constraint at times during the conversion;
at least for subsequent code words, for multiple information word values, the conversion using the C1 conversion code includes selecting between multiple predetermined alternative code word values for the same information word value, the alternative code word values have mutually different beginning parts, and the selection depends on an end part of the immediately preceding code word so that the sequence of code words complies with the runlength constraint;
the conversion of each information word using the C2 conversion code includes selecting between multiple predetermined alternative code word values for each information word value, the second alternative code word values include values having potentially mutually different effects on complying with the second constraint, and the selection depends on the effect of the selection on meeting the second constraint so that the sequence of code words complies with the second constraint.

8 more elements

An encoding device comprising:

an input that receives an information signal representing information words having n-bit values;
means for converting the information words into code words, some of the code words having m1-bit values and other of the code words having m2-bit values, m1, m2 and n are integers and m2>m1>n;
and
an output that transmits a code signal representing a sequence of code words, subsequent code words of the sequence immediately following preceding code words;
wherein:
the converting of information words into the corresponding m1-bit code words is in accordance with a conversion code C1;
the converting of information words into corresponding m2-bit code words is in accordance with a conversion code C2;
the sequence of code words complies with a runlength constraint and with a second constraint that is at least partially independent of the runlength constraint;
the converting includes selecting between conversion code C1 and conversion code C2 depending on a measure of the second constraint at times during the conversion;
for code words that immediately follow a previous code word in the sequence of code words, for multiple information word values, the conversion using the C1 conversion code includes selecting between multiple predetermined alternative code word values for the same information word value, the alternative code word values have mutually different beginning parts, and the selection depends on an end part of the immediately preceding code word so that the sequence of code words complies with the runlength constraint;
the conversion of each information word using the C2 conversion code includes selecting between multiple predetermined alternative code word values for each information word value, the second alternative code word values include values having potentially mutually different effects on complying with the second constraint, and the selection depends on the effect of the selection on meeting the second constraint so that the sequence of code words complies with the second constraint.

8 more elements

A decoding device comprising:

an input that receives a code word signal that represents a sequence of code words, subsequent code words of the sequence immediately following preceding code words, some code words having m1-bit values and other code words having m2-bit values;
means for determining whether a code word is an m1-bit code word or an m2-bit code word;
means for converting the m1-bit and m2-bit code words into corresponding information words having n-bit values, the converting depending on the determination, wherein m1, m2 and n are integers, and m2>m1>n;
and
an output that transmits the sequence of information words;
wherein:
the converting of information words into the corresponding m1-bit code words is in accordance with a conversion code C1;
the converting of information words into corresponding m2-bit code words is in accordance with a conversion code C2;
the sequence of code words complies with a runlength constraint and with a second constraint that is at least partially independent of the runlength constraint;
the converting includes selecting between conversion code C1 and conversion code C2 depending on a measure of the second constraint at times during the conversion;
for subsequent code words, for multiple information word values, the conversion using the C1 conversion code includes selecting between multiple predetermined alternative code word values for the same information word value, the alternative code word values have mutually different beginning parts, and the selection depends on an end part of the immediately preceding code word so that the sequence of code words complies with the runlength constraint;
the conversion of each information word using the C2 conversion code includes selecting between multiple predetermined alternative code word values for each information word value, the second alternative code word values include values having potentially mutually different effects on complying with the second constraint, and the selection depends on the effect of the selection on meeting the second constraint so that the sequence of code words complies with the second constraint.

9 more elements

Dependencies are inferred from the claim text.

Converting information words into different length code words depending on a property of a code signal

Life of this patent

Converting information words into different length code words depending on a property of a code signal

Life of this patent

Abstract

Claims49