Data modulating/demodulating method and apparatus for optical recording medium

A data modulating method for an optical recording medium wherein a source data is converted under a fixed code conversion rate and a (d, k) constraint, the method comprising the steps of:

• preparing a set of conversion tables where the source data is converted into a coded data said set of conversion tables including conversion tables for converting 2, 4, 6 and 8-bit data into 3, 6, 9 and 12-bit data respectively;
• converting the source data into a bit stream of coded data using the conversion tables;
• and
• converting said coded data stream into a channel data stream to be recorded on the optical recording medium,
• wherein the code conversion rate of the conversion tables is ⅔ such that source data of a 2, 4, 6 and 8-bit data are converted into a 3, 6, 9 and 12-bit data respectively, wherein the converted coded data stream maintains a (d, k) constraint of (1, 8), and wherein no merging bit is used between converted coded data.

A data demodulating method for an optical recording medium wherein a channel data recorded on the optical recording medium is decoded, the method comprising the steps of:

• detecting the channel data from the optical recording medium;
• preparing a first decoding table in which an decoded data corresponding to the channel data is registered, said first decoding table including decoding tables for decoding 2, 4, 6 and 8-bit data into 3, 6, 9, and 12-bit data respectively;
• preparing a second decoding table registered with a decoded data identical to an individual coded data selected in response to a specific source data such that a digital sum value of the channel data becomes a minimum value upon encoding, said second decoding table including decoding tables for decoding 2 and 4-bit data into 3 and 6-bit data respectively;
• and
• decoding the channel data detected from the optical recording medium using the first and second tables.

A data modulating apparatus for an optical recording medium wherein a source data is converted under a fixed code conversion rate and a (d, k) constraint, the apparatus comprising:

• a first set of conversion tables where the source data is converted into a coded data said first set of conversion tables including conversion tables for converting 2, 4, 6 and 8-bit data into 3, 6, 9 and 12-bit data respectively;
• a second set of conversion tables for the specific source data to be converted into a coded data said second set of conversion tables including conversion tables for converting 2 and 4-bit data into 3 and 6-bit data respectively;
• first converting means for converting the source data into a first and a second bit stream of coded data using both of sets of the conversion tables;
• means for calculating a digital sum value for the first and second bit streams whenever the second coded data converted from the specific source data is found;
• means for selecting the coded data stream that has smaller digital sum value;
• and
• second converting means for converting the selected code data stream into a channel data stream to be recorded on the optical recording medium;
• wherein the code conversion rate of the conversion tables is ⅔ such that source data of a 2, 4, 6 or 8-bit data are encoded into a 3, 6, 9 or 12-bit data respectively, wherein the converted coded data stream maintains a (d, k) constraint of (1, 8), and wherein no merging bit is used between converted coded data.

A data modulating apparatus for an optical recording medium wherein a source data is converted under a fixed code conversion rate and a (d, k) constraint, the apparatus comprising:

• a set of conversion tables where the source data is converted into a coded data, said set of conversion tables including conversion tables for converting 2, 4, 6 and 8-bit data into 3, 6, 9 and 12-bit data respectively;
• first converting means for converting the source data into a bit stream of coded data using the conversion tables;
• and
• second converting means for converting the said coded data stream into a channel data stream to be recorded on the optical recording medium,
• wherein the code conversion rate of the conversion tables is ⅔ such that source data of a 2, 4, 6 and 8-bit data are converted into a 3, 6, 9 and 12-bit data respectively, wherein the converted coded data stream maintains a (d, k) constraint of (1, 8), and wherein no merging bit is used between converted coded data.

A data demodulating apparatus for an optical recording medium wherein a channel data recorded on the optical recording medium is decoded, the apparatus comprising:

• detecting means for detecting the channel data from the optical recording medium;
• first decoding means for decoding the channel data detected from the optical recording medium using a first decoding table in which an decoded data corresponding to the channel data is registered, said first decoding table including decoding tables for decoding 2, 4, 6 and 8-bit data into 3, 6, 9, and 12-bit data respectively;
• and
• second decoding means for decoding the channel data detected from the optical recording medium using a second decoding table registered with a decoded data identical to an individual coded data selected in response to a specific source data such that a digital sum value of the channel data becomes a minimum value upon encoding, said second decoding table including decoding tables for decoding 2 and 4-bit data into 3 and 6-bit data respectively.