Abstract: A method of modulating a source data to a code data under condition of a given code rate and run length limited (rll). The method including (a) inputting the source data, and (b) modulating the source data into code data by converting source data of 2 bits into code data of 3 bits under a condition of a given code rate. Further, the modulating step (b) further includes converting source data of 4 bits into code data of 6 bits, source data of 6 bits into code data of 9 bits, and source data of 8 bits into code data of 12 bits, based on a bit sequence of the source data.

Abstract: The present invention relates to method and apparatus of converting a series of data words into modulated signals. This method divides a data word, which a sync signal is to be added in front or rear of when it is written in a recording medium, into two or more word segments, generates for each word segment a number of intermediate sequences by combining mutually different digital words with that word segment, scrambles these intermediate sequences to form alternative sequences, translates each alternative sequence into a (d,k) constrained sequence, checks how many undesired sub-sequences are contained in each (d,k) constrained sequence, and selects one (d,k) constrained sequence for recording on an optical or magneto-optical recording medium among the (d,k) constrained sequences not having the undesired sub-sequence. Applying this method to a modulating device, DSV control can be conducted by much simpler hardware.

Abstract: The present invention relates to method and apparatus for suppressing a DC component of coded sequence with no additional bit for suppressing a DC component, and for decoding the coded sequence. The present modulating method includes modulating the source data to a coded data based on at least one mapping table, the mapping table including a first table and a second table containing coded data corresponding to the source data, the first table being a 2/3 table containing 3-bit coded data for 2-bit source data, and the second table being a 4/6 table containing 6-bit coded data for 4-bit source data, wherein one of the first table and the second table is selected according to a bit sequence of the source data; and recording the coded data onto the optical recording medium.

Abstract: The present invention relates to method and apparatus of converting a series of data words into modulated signals. This method divides a data word, which a sync signal is to be added in front or rear of when it is written in a recording medium, into two or more word segments, generates for each word segment a number of intermediate sequences by combining mutually different digital words with that word segment, scrambles these intermediate sequences to form alternative sequences, translates each alternative sequence into a (d, k) constrained sequence, checks how many undesired sub-sequences are contained in each (d, k) constrained sequence, and selects one (d, k) constrained sequence for recording on an optical or magneto-optical recording medium among the (d, k) constrained sequences not having the undesired sub-sequence. Applying this method to a modulating device, DSV control can be conducted by much simpler hardware.

Abstract: A method and apparatus of converting a series of data words into modulated signals are provided. This method generates for each data word a number of intermediate sequences by combining mutually different digital words with that data word, scrambles these intermediate sequences to form alternative sequences, translates each alternative sequence into a (d,k) constrained sequence, checks whether each (d,k) constrained sequence contains undesired sub-sequence of more than kSET “0”s where kSET is smaller than k, and selects one (d,k) constrained sequence for recording on an optical or magneto-optical recording medium among the (d,k) constrained sequences not having the undesired sub-sequence, thereby recording edge information more frequently which will result in stable clock while conducting DSV control normally.

Abstract: A method for modulating digital data and apparatus therefor is capable of determining a digital data stream coded by Run Length Limited swiftly and precisely so as to record data in a recording medium. The digital data modulating method includes the steps of comparing a preset critical value and DSV (Digital Sum Value) of a certain digital data stream, computing the penalty of the digital data stream by multiplying the number of the time that the DSV of the digital data stream is larger than the critical value by a preset weight value of the critical value, comparing the penalty of the digital data and a penalty of another digital data stream and selecting a digital data stream with a smaller penalty as the digital data stream. Therefore, with the method for modulating digital data and apparatus therefor, the digital data stream which will be modulated among a number of digital data streams can be selected precisely and swiftly.

Abstract: A digital data modulating method wherein the last unit of a block consisting of predetermined units is received and a block is obtained which does not infringe A k-constraint in AN RLL code having (d, k) constraints on the basis of a modulation data table of a predetermined unit. A source code word to be modulated to a code word can be quickly and accurately determined while satisfying the (d, k) constraint of the RLL code between the blocks having a predetermined size.

Abstract: A method for modulating digital data and apparatus therefor is capable of determining digital data stream coded by Run Length Limited (hereinafter as RLL) swiftly and precisely so as to record data in a record medium. To achieve the method and apparatus, the digital data modulating method includes the steps of comparing a preset critical value and DSV of a certain digital data stream, computing the penalty of the digital data stream by multiplying the number of the time that the DSV of the digital data stream is larger than the critical value by a preset weight value of the critical value and comparing the penalty of the digital data and a penalty of another digital data stream and determining a digital data stream with a smaller penalty for the digital data stream.

Abstract: A digital data modulating method wherein the last unit of a block consisting of predetermined units is received and a block is obtained which does not infringe the k-constraint in the RLL code having the (d, k) constraints on the basis of a modulation data table of a predetermined unit. The source code word to be modulated to a code word can be quickly and accurately determined while satisfying the (d, k) constraint of the RLL code between the blocks having a predetermined size.

Abstract: A data modulating/demodulating method and apparatus for an optical recording medium that is capable of keeping a digital sum value at a minimum value. In the method, a source data is converted into a coded data by a first conversion table in which the coded data corresponding to the source data is registered. The coded data is converted into a first channel data suitable for the optical recording medium. A second conversion table is registered with a coded data for suppressing a DC component in correspondence with a specific source data such that a digital sum value of the first channel data becomes a minimum value. The specific source data is converted into the coded data for a direct current restraint by the second decoding table and then converted into a second channel data. A digital sum value for the first and second channel data is calculated to select a coded data in which the digital sum value becomes a minimum value from the first and second conversion tables.

Abstract: The present invention relates to method and apparatus of converting a series of data words into modulated signals. This ethod generates for each data word a number of intermediate sequences by combining mutually different digital words with that data word, scrambles these intermediate sequences to form alternative sequences, translates each alternative sequence into a (d,k) constrained sequence, checks whether each (d,k) constrained sequence contains undesired sub-sequence of more than kSET “0”s where kSET is smaller than k, and selects one (d,k) constrained sequence for recording on an optical or magneto-optical recording medium among the (d,k) constrained sequences not having the undesired sub-sequence, thereby recording edge information more frequently which will result in stable clock while conducting DSV control normally.

Abstract: The present invention relates to method and apparatus of converting a series of data words into modulated signals. This method divides a data word, which a sync signal is to be added in front or rear of when it is written in a recording medium, into two or more word segments, generates for each word segment a number of intermediate sequences by combining mutually different digital words with that word segment, scrambles these intermediate sequences to form alternative sequences, translates each alternative sequence into a (d, k) constrained sequence, checks how many undesired sub-sequences are contained in each (d, k) constrained sequence, and selects one (d, k) constrained sequence for recording on an optical or magneto-optical recording medium among the (d, k) constrained sequences not having the undesired sub-sequence. Applying this method to a modulating device, DSV control can be conducted by much simpler hardware.

Abstract: A data modulating/demodulating method and apparatus for an optical recording medium that is capable of keeping a digital sum value at a minimum value. In the method, a source data is converted into a coded data by a first conversion table in which the coded data corresponding to the source data is registered. The coded data is converted into a first channel data suitable for the optical recording medium. A second conversion table is registered with a coded data for suppressing a DC component in correspondence with a specific source data such that a digital sum value of the first channel data becomes a minimum value. The specific source data is converted into the coded data for a direct current restraint by the second decoding table and then converted into a second channel data. A digital sum value for the first and second channel data is calculated to select a coded data in which the digital sum value becomes a minimum value from the first and second conversion tables.