Information reproducing method judging a multivalued level of a present cell by referring to judged multivalued levels of a preceding cell and an ensuing cell
AssigneeRicoh Company, Ltd.
InventorsAkihiko Shimizu, Koubun Sakagami, Hiroyuki Miyata, Yasuhide Fujiwara
Life of this patent
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Abstract
A mark representing information of a multivalued level is recorded in each of cells arranged in a recording medium. Upon reproducing the multivalued level from a reproduction signal of the recording medium, the multivalued level of a present cell is judged by referring to a judged multivalued level of a preceding cell preceding the present cell or an ensuing cell ensuing the present cell, or by referring to the judged multivalued levels of both the preceding cell and the ensuing cell.
Claims61
An information recording method for recording a mark representing information of a multivalued level on each of cells of an information recording medium, the method comprising the step of:
- recording an M-valued mark on one cell in every predetermined number of cells so as to intervene between cells having N-valued marks, where N is an integer equal to or larger than 3, and M is an integer smaller than N.
An information recording device recording a mark representing information of a multivalued level on each of cells of an information recording medium, the device comprising:
- a multivalued-level converting unit converting input information into a predetermined number of N-valued cell level data items and one M-valued cell level data item, where N is an integer equal to or larger than 3, and M is an integer smaller than N;
- and
- a recording unit recording N-valued marks corresponding to said N-valued cell level data items and an M-valued mark corresponding to said M-valued cell level data item so that said M-valued mark is recorded on one cell in every predetermined number of cells so as to intervene between cells having the N-valued marks.
An information reproducing method for reproducing a multivalued level from a reproduction signal of a recording medium in which a mark representing information of said multivalued level is recorded on a cell, the method comprising:
- a judging step of judging a multivalued level of a present cell by referring to a judged multivalued level of at least one of a preceding cell preceding said present cell and an ensuing cell ensuing said present cell.
An information reproducing method for reproducing a multivalued level from a reproduction signal of an information recording medium in which a mark representing information of said multivalued level is recorded on each of cells so that an M-valued mark is recorded on one cell in every predetermined number of cells so as to intervene between cells having N-valued marks, where N is an integer equal to or larger than 3, and M is an integer smaller than N, the method comprising the step of:
- switching numbers of multivalued judgment levels between N and M with each predetermined number of the cells so as to judge a multivalued level of a present cell having one of the N-valued mark and the M-valued mark.
An information reproducing device reproducing a multivalued level from a reproduction signal of a recording medium in which a mark representing information of said multivalued level is recorded on a cell, the device comprising:
- an A/D converting unit converting said reproduction signal into digital data;
- a multivalued level data retaining unit retaining multivalued level data of a preceding cell preceding a present cell;
- a judging-criteria changing unit changing criteria for judging a multivalued level of said present cell according to individual multivalued levels of said preceding cell;
- and
- an operation unit determining multivalued level data of said present cell according to the criteria changed by said judging-criteria changing unit based on said digital data converted by said A/D converting unit and said multivalued level data of said preceding cell retained by said multivalued level data retaining unit.
An information reproducing device reproducing a multivalued level from a reproduction signal of a recording medium in which a mark representing information of said multivalued level is recorded on a cell, the device comprising:
- an A/D converting unit converting said reproduction signal into digital data;
- a digital-data retaining unit retaining said digital data converted by said A/D converting unit;
- an ensuing cell level operation unit determining multivalued level data of an ensuing cell ensuing a present cell prior to determining multivalued level data of said present cell;
- a judging-criteria changing unit changing criteria for judging a multivalued level of said present cell according to individual multivalued levels of said ensuing cell;
- and
- an operation unit determining the multivalued level data of said present cell according to the criteria changed by said judging-criteria changing unit based on said digital data retained by said digital-data retaining unit and said multivalued level data of said ensuing cell determined by said ensuing cell level operation unit.
An information reproducing device reproducing a multivalued level from a reproduction signal of a recording medium in which a mark representing information of said multivalued level is recorded on a cell, the device comprising:
- an A/D converting unit converting said reproduction signal into digital data;
- a digital-data retaining unit retaining said digital data converted by said A/D converting unit;
- a multivalued level data retaining unit retaining multivalued level data of a preceding cell preceding a present cell;
- an ensuing cell level operation unit determining multivalued level data of an ensuing cell ensuing said present cell prior to determining multivalued level data of said present cell;
- a judging-criteria changing unit changing criteria for judging a multivalued level of said present cell according to individual multivalued levels of said preceding cell and said ensuing cell;
- and
- an operation unit determining multivalued level data of said present cell according to the criteria changed by said judging-criteria changing unit based on said digital data retained by said digital-data retaining unit, said multivalued level data of said preceding cell retained by said multivalued level data retaining unit, and said multivalued level data of said ensuing cell determined by said ensuing cell level operation unit.
An information reproducing device reproducing a multivalued level from a reproduction signal of a recording medium in which a mark representing information of said multivalued level is recorded on a cell, the device comprising:
- an A/D converting unit converting said reproduction signal into digital data;
- a digital-data retaining unit retaining said digital data;
- a primary operation unit judging a multivalued level of said digital data according to the reproduction signal deriving only from the mark of a present cell;
- a judged-value retaining unit temporarily retaining the judged multivalued level judged by said primary operation unit;
- an ensuing cell level operation unit determining a multivalued level of an ensuing cell ensuing said present cell prior to re-judging the multivalued level of said present cell;
- a reference judged value selecting unit selecting either of the judged multivalued levels of a preceding cell preceding said present cell and said ensuing cell according to an amount of an inter-code interference from either of said preceding cell and said ensuing cell to the reproduction signal of said present, cell;
- and
- a re-judgment operation unit re-judging the multivalued level of said present cell by referring to the judged multivalued level selected by said reference judged value selecting unit.
An information reproducing device reproducing a multivalued level from a reproduction signal of an information recording medium in which a mark representing information of said multivalued level is recorded on each of cells so that an M-valued mark is recorded on one cell in every predetermined number of cells so as to intervene between cells having N-valued marks, where N is an integer equal to or larger than 3, and M is an integer smaller than N, the device comprising:
- an A/D converting unit converting the reproduction signal into digital data;
- and
- a multivalued-level judging unit judging a multivalued level of the digital data of a present cell having one of the N-valued mark and the M-valued mark by switching numbers of multivalued judgment levels between N and M with each predetermined number of the cells.
An information recording and reproducing device reproducing a multivalued level from a reproduction signal of a writable recording medium in which a mark representing information of said multivalued level is recorded on a cell, the device comprising:
- an A/D converting unit converting said reproduction signal into digital data;
- a digital-data retaining unit retaining said digital data;
- a primary operation unit judging a multivalued level of said digital data according to the reproduction signal deriving only from the mark of a present cell;
- a judged-value retaining unit temporarily retaining the judged multivalued level judged by said primary operation unit;
- an ensuing cell level operation unit determining a multivalued level of an ensuing cell ensuing said present cell prior to re-judging the multivalued level of said present cell;
- a reference judged value selecting unit selecting either of the judged multivalued levels of a preceding cell preceding said present cell and said ensuing cell according to an amount of an inter-code interference from either of said preceding cell and said ensuing cell to the reproduction signal of said present cell;
- a re-judgment operation unit re-judging the multivalued level of said present cell by referring to the judged multivalued level selected by said reference judged value selecting unit;
- a learned-pattern recording unit recording all combination patterns of a group of three marks as learned pattern information of known multivalued levels in said recording medium;
- a learning unit reproducing said learned pattern information from said recording medium;
- and
- a criterion-table creating unit creating at least one criterion table according to level-value information of the reproduction signal obtained from said learned pattern information by said learning unit, the criterion table being used for judging the multivalued level of said present cell.
An information recording medium in which a mark representing information of a multivalued level is recorded on a cell,
- wherein all combination patterns of a group of three marks are recorded beforehand as learned pattern information of known multivalued levels so as to be used for creating at least one criterion table used for judging the multivalued level.
An information recording medium in which a mark representing information of a multivalued level is recorded on a cell, the information recording medium comprising:
- a learned pattern information area in which all combination patterns of a group of three marks are recorded beforehand as learned pattern information of known multivalued levels so as to be used for creating at least one criterion table used for judging the multivalued level, the learned pattern information area being located outside a user data area.
An information recording medium in which a mark representing information of a multivalued level is recorded on each of cells,
- wherein an M-valued mark is recorded on one cell in every predetermined number of cells so as to intervene between cells having N-valued marks, where N is an integer equal to or larger than 3, and M is an integer smaller than N.
Dependencies are inferred from the claim text.