Modulating method and demodulating method as well as modulating apparatus and demodulating apparatus

A modulating apparatus for modulating digital data of a basic data length of m bits into a variable length code (d, k;m, n;r) of a basic code length of n bits, comprising:

• storage means for storing therein a plurality of tables for converting the digital data into the variable length code wherein, where the distance between adjacent ones of the digital data is represented by T, the minimum reversal distance Tmin is equal to or greater than 2.0 T and the minimum length d of a run of a same symbol is equal to or greater than 4;
• discriminating means for discriminating the binding length r of the digital data;
• and
• selecting means for selecting one of the tables in said storage means in accordance with a result of discrimination of said discriminating means.

A demodulating apparatus for demodulating a variable length code (d, k;m, n;r) of a basic code length of n bits into digital data of a basic data length of m bits, comprising:

• storage means for storing therein a plurality of tables for converting the variable length code wherein, where the distance between adjacent ones of the digital data is represented by T, the minimum reversal distance Tmin is equal to or greater than 2.0 T and the minimum length d of a run of a same symbol is equal to or greater than 4 into the digital data;
• discriminating means for discriminating the conversion length of the variable length code;
• and
• selecting means for selecting one of the tables in said storage means in accordance with a result of discrimination of said discriminating means.

A modulating apparatus for modulating digital data of a basic data length of m bits into a variable length code (d, k;m, n;r) of a basic code length of n bits, comprising:

• storage means for storing therein a plurality of tables for converting the digital data into the variable length code wherein, where the distance between adjacent ones of the digital data is represented by T, the minimum reversal distance Tmin of the variable length code is equal to or greater than 2.0 T, the maximum reversal distance Tmax is equal to or smaller than 9.2 T, the minimum length d of a run of a same symbol is equal to or greater than 4, the last 5 bits of a code word of the variable length code are all 0 except when the binding length r of the digital data is 1, and the binding length r of the variable length code is equal to r=5;
• discriminating means for discriminating the binding length r of the digital data;
• and
• selecting means for selecting one of the tables in said storage means in accordance with a result of discrimination of said discriminating means.

A demodulating apparatus for demodulating a variable length code (d, k;m, n;r) of a basic code length of n bits into digital data of a basic data length of m bits, comprising:

• storage means for storing therein a plurality of tables for converting the variable length code wherein, where the distance between adjacent ones of the digital data is represented by T, the minimum reversal distance Tmin of the variable length code is equal to or greater than 2.0 T, the maximum reversal distance Tmax is equal to or smaller than 9.2 T, the minimum length d of a run of a same symbol is equal to or greater than 4, the last 5 bits of a code word of the variable length code are all 0 except when the binding length r of the digital data is 1, and the binding length r of the variable length code is equal to r=5 into the digital data;
• discriminating means for discriminating the conversion length of the variable length code;
• and
• selecting means for selecting one of the tables in said storage means in accordance with a result of discrimination of said discriminating means.

A modulating apparatus for modulating digital data of a basic data length of m bits into a variable length code (d, k;m, n;r) of a basic code length of n bits, comprising:

• first storage means for storing therein a first conversion table for successively varying the basic code length n of the variable length code by n1 bits or n2 bits each time the basic data length m of the digital data varies by a predetermined number of bits, n1 being different from n2;
• second storage means for storing therein a second conversion table for successively varying the basic code length n of the variable length code by n2 bits or n1 bits each time the basic data length m of the digital data varies by the predetermined number of bits;
• and
• composing means for composing the code words of the variable length code after conversion in accordance with the first and the second conversion tables.

A demodulating apparatus for demodulating a variable length code (d, k;m, n;r) of a basic code length of n bits into digital data a basic data length of m bits, comprising:

• first storage means for storing therein a first conversion table for converting the variable length code into the digital data so that the basic data length m of the digital data may be successively varied by a predetermined number of bits each time the basic code length n of the variable length code successively varies by n1 bits or n2 bits, n1 being different from n2;
• second storage means for storing therein a second conversion table for converting the variable length code into the digital data so that the basic data length m of the digital data may be successively varied by the predetermined number of bits each time the basic code length n of the variable length code successively varies by n2 bits or n1 bits;
• and
• composing means for composing the digital data after conversion in accordance with the first and second conversion tables.

A modulating apparatus for modulating digital data of a basic data length of m bits into a variable length code (d, k;m, n;r) of a basic code length of n bits, comprising:

• first converting means for inputting the digital data and converting the input digital data into a first code train in accordance with a first conversion table;
• second converting means for inputting the digital data and converting the input digital data into a second code train in accordance with a second conversion table;
• multiplexing means for receiving the first code train from said first converting means and the second code train from said second converting means;
• and
• timing managing means for inputting the digital data, detecting a boundary of a block of the input digital data based on a synchronizing signal, and sending out, when a boundary of a block is detected, a control signal to said multiplexing means so that the output of said multiplexing means is changed over from the first code train from said first converting means to the second code train from said second converting means.

A demodulating apparatus for demodulating a variable length code (d, k;m, n;r) of a basic code length of n bits into digital data of a basic data length of m bits, comprising:

• first converting means for inputting the variable length code and converting the input variable length code into first demodulation data in accordance with a first conversion table;
• second converting means for inputting the variable length code and converting the input variable length code into second demodulation data in accordance with a second conversion table;
• multiplexing means for receiving the first demodulation data from said first converting means and the second demodulation data from said second converting means;
• and
• timing managing means for inputting the variable length code, detecting a particular code train from the input variable length code and sending out, when the particular code train is detected, a control signal to said multiplexing means so that the output of said multiplexing means is changed over from the second demodulation data from said second converting means to the first demodulation data from said first converting means.