Method of encoding position information

A method of reading position information from a group of recording units on a recording medium, each group having a predetermined number of recording units, each recording unit having a predetermined number of information bits for recording a position information code indicating its position within the group, each recording unit within a group having an information code that differs from the information codes of every other recording unit within that group, the position information code being recorded in the form of logic "0" and logic "1" bits, the number of information bits being less than one half the number of recording units within the group, the position information codes being composed such that,

• the position information code for any selected recording unit differs by one information unit from the position information codes for each recording unit spaced by one recording unit from the selected recording unit;
• the position information code for the selected recording unit differs by two information units from the position information codes for each recording unit spaced by two recording units from the selected recording unit;
• the position information code for the selected recording unit differs by three information units from the position information codes for each recording unit spaced by three recording units from the selected recording unit,
• the method including the steps of:
• when one of said bits of a position information code is unclear, assuming that said unclear bit is a logic 0 to form a first assumed position information code;
• determining whether the first assumed position information code matches a position information code for any of the recording units within the group,
• if the first assumed position information code matches a first identical position information code, substituting the first identical information code for the unclear position information code;
• if the first assumed position information code does not match any position information code within the group, executing the following steps;
• assuming that said unclear bit is a logic 1 to form a second assumed position information code, determining whether the second assumed position information code matches a position information code for any of the recording units within the group;
• if the second assumed position information code matches a second identical position information code, substituting the second identical information code for the unclear position information code.

A method of reading position information from a group of recording units on a recording medium, each group having a predetermined number of recording units, each recording unit having a predetermined number of information bits for recording a position information code indicating its position within the group, each recording unit within a group having an information code that differs from the information codes of every other recording unit within that group, the position information code being recorded in the form of logic "0" and logic "1" bits, the number of information bits being less than one half the number of recording units, the position information codes being composed such that,

• the position code for any selected recording unit differs by one information unit from the position information codes for each recording unit spaced by one recording unit from the selected recording unit;
• the position information code for the selected recording unit differs by two information units from the position information codes for each recording unit spaced by two recording units from the selected recording unit;
• the position information code for the selected recording unit differs by three information units from the position information codes for a each recording unit spaced by three recording units from the selected recording unit,
• the method including the steps of:
• when one of said bits of a position information code is unclear, assuming that said unclear bit is a logic 1 to form a first assumed position information code;
• determining whether the first assumed position information code matches a position information code for any of the recording units within the group,
• if the first assumed position information code matches a first identical position information code, substituting the first identical information code for the unclear position information code;
• if the first assumed position information code does not match any position information code within the group, executing the following steps;
• assuming that said unclear bit is a logic 0 to form a second assumed position information code, determining whether the second assumed position information code matches a position information code for any of the recording units within the group;
• if the second assumed position information code matches a second identical position information code, substituting the second identical information code for the unclear position information code.

A method of encoding position information for a group of recording units on a recording medium, the recording medium having at least one group of recording portions, each group having a predetermined number of recording units, the method including the steps of:

• for each recording unit, establishing a predetermined number of information units indicating the position of the recording unit within the group, each recording unit within a group having an information code that differs from the information codes of every other recording unit within that group;
• encoding the information units such that;
• the position information code for any selected recording unit differs by one information unit from the position information codes for each recording unit spaced by one recording unit from the selected recording portion;
• the position information code for the selected recording unit differs by two information units from the position information codes for each recording unit spaced by two recording units from the selected recording unit;
• the position information code for the selected recording unit differs by three information units from the position information codes for each recording unit spaced by three recording units from the selected recording unit;
• and
• the number of information units is less than one half the number of recording units within the group.

A method of encoding position information for a group of recording units on a recording medium, the recording medium having at least one group of recording units, each group having a predetermined number of recording units, each recording unit having a predetermined number of information units for recording a position information code indicating its position within the group, each recording unit within a group having an information code that differs from the information codes of every other recording unit within that group, each information unit being capable of storing first and second values, the method including the step of encoding the information units such that;

• the position information code for any selected recording unit differs by one information unit from the position information codes for each recording unit spaced by one recording unit from the selected recording unit;
• the position information code for the selected recording unit differs by two information units from the position information codes for each recording unit spaced by two recording units from the selected recording unit;
• the position information code for the selected recording unit differs by three information units from the position information codes for each recording unit spaced by three recording units from the selected recording unit;
• and
• at least one recording unit has a position information code including at least first, second and third information units, the second information unit being positioned between the first and third information units, said first and third information units storing the first value and the second information unit storing the second value.

A recording medium having at least one group of recording units, each group having a predetermined number of recording units, each recording unit having a predetermined number of information units for recording a position information code indicating its position within the group, each recording unit within a group having an information code that differs from the information codes of every other recording unit within that group;

• the number of information units being less than one half the number of recording units within the group;
• the information units being encoded such that:
• the position information code for any selected recording unit differs by one information unit from the position information codes for each recording unit spaced by one recording unit from the selected recording unit;
• the position information code for the selected recording unit differs by two information units from the position information codes for each recording unit spaced by two recording units from the selected recording unit;
• and
• the position information code for the selected recording unit differs by three information units from the position information codes for each recording unit spaced by three recording units from the selected recording unit.

A recording medium having at least one group of recording units, each group having a predetermined number of recording units, each recording unit having a predetermined number of information units for recording a position information code indicating its position within the group, each recording unit within a group having an information code that differs from the information codes of every other recording unit within that group, each information unit being capable of storing first and second values;

• the information units being encoded such that:
• the position information code for any selected recording unit differs by one information unit from the position information codes for each recording unit spaced by one recording unit from the selected recording unit;
• the position information code for the selected recording unit differs by two information units from the position information codes for each recording unit spaced by two recording units from the selected recording unit;
• and
• the position information code for the selected recording unit differs by three information units from the position information codes for each recording unit spaced by three recording units from the selected recording unit;
• and
• at least one recording unit has a position information code including at least first, second and third information units, the second information unit being positioned between the first and third information units, said first and third information units storing the first value and the second information unit storing the second value.

A method of encoding position information of each recording portion on a recording medium having a plurality of recording portions, each recording portion having position information encoded by a predetermined number of information units, comprising the step of composing position information such that:

• said information unit forms a position pattern consisting of binaries of "0" and "1" having at least three bits;
• said position pattern consists of a predetermined number of "0"s and "1"s;
• and
• the position pattern of a particular portion is different by one in the number of "0"s or "1"s from the position pattern of a recording portion which is spaced by one recording portion from said particular recording portion, by two in the number of "0"s or "1"s from the position pattern of a recording portion which is spaced by two recording portions from said particular recording portion, and by three in the number of "0"s or "1"s from the position pattern of a recording portion which is spaced by three recording potions from said particular recording portion.

A method of encoding position information for a group of recording units on a recording medium, the recording medium having at least one group of recording units, each group having a predetermined number of recording units N, each recording unit having a predetermined number of information units for recording a position information code indicating its position within the group, each recording unit within a group having an information code that differs from the information codes of every other recording unit within that group, the number of information units being less than one half N, the method including the step of composing position information codes such that:

• the position information code for any selected recording unit differs by one information unit from the position information codes for each recording unit spaced by one recording unit from the selected recording unit, and for each recording unit spaced by N-1 recording units from the selected recording unit;
• the position information code for the selected recording unit differs by two information units from the position information codes for each recording unit spaced by two recording units from the selected recording unit, and for each recording unit spaced by N-2 recording units from the selected recording unit;
• the position information code for the selected recording unit differs by at least three information units from the position information codes for each recording unit spaced by more than two and less than N-2 recording units from the selected recording unit.

A method of reading position information from a group of recording units on a recording medium, each group having a predetermined number of recording units, each recording unit having a predetermined number N of information bits for recording a position information code indicating its position within the group, each recording unit within a group having an information code that differs from the information codes of every other recording unit within that group, the position information code being recorded in the form of logic "0" and logic "1" bits, the number of information bits being less than one half N, the position information codes being composed such that,

• the position information code for any selected recording unit differs by one information unit from the position information codes for each recording unit spaced by one recording unit from the selected recording unit, and for each recording unit spaced by N-1 recording units from the selected recording unit;
• the position information code for the selected recording unit differs by two information units from the position information codes for each recording unit spaced by two recording units from the selected recording unit, and for each recording unit spaced by N-2 recording units from the selected recording unit;
• the position information code for the selected recording unit differs by at least three information units from the position information codes for each recording unit spaced by more than two and less than N-2 recording units from the selected recording unit;
• the method including the steps of:
• when one of said bits of a position information code is unclear, assuming that said unclear bit is a logic 0 to form a first assumed position information code;
• determining whether the first assumed position information code matches a position information code for any of the recording units within the group.
• if the first assumed position information code matches a first identical position information code, substituting the first identical information code for the unclear position information code;
• if the first assumed position information code does not match any position information code within the group, executing the following steps;
• assuming that said unclear bit is a logic 1 to form a second assumed position information code, determining whether the second assumed position information code matches a position information code for any of the recording units within the group;
• if the second assumed position information code matches a second identical position information code, substituting the second identical information code for the unclear position information code.

A method of encoding position information for a group of recording units on a recording medium, the recording medium having at least one group of recording portions, each group having a predetermined number N of recording units, the method including the steps of:

• for each recording unit, establishing a predetermined number of information units indicating the position of the recording unit within the group, each recording unit within a group having an information code that differs from the information codes of every other recording unit within that group;
• encoding the information units such that;
• the position information code for any selected recording unit differs by one information unit from the position information codes for each recording unit spaced by one recording unit from the selected recording unit, and for each recording unit spaced by N-1 recording units from the selected recording unit;
• the position information code for the selected recording unit differs by two information units from the position information codes for each recording unit spaced by two recording units from the selected recording unit, and for each recording unit spaced by N-2 recording units from the selected recording unit;
• the position information code for the selected recording unit differs by at least three information units from the position information codes for each recording unit spaced by more than two and less than N-2 recording units from the selected recording unit;
• and
• the number of information units is less than one half N.

A recording medium having at least one group of recording units, each group having a predetermined number N of recording units, each recording unit having a predetermined number of information units for recording a position information code indicating its position within the group, each recording unit within a group having an information code that differs from the information codes of every other recording unit within that group;

• the number of information units being less than one half N;
• the information units being encoded such that:
• the position information code for any selected recording unit differs by one information unit from the position information codes for each recording unit spaced by one recording unit from the selected recording unit, and for each recording unit spaced by N-1 recording units from the selected recording unit;
• the position information code for the selected recording unit differs by two information units from the position information codes for each recording unit spaced by two recording units from the selected recording unit, and for each recording unit spaced by N-2 recording units from the selected recording unit;
• and
• the position information code for the selected recording unit differs by at least three information units from the position information codes for each recording unit spaced by more than two and less than N-2 recording units from the selected recording unit.

A recording medium having at least one group of recording units, each group having a predetermined number N of recording units, each recording unit having a predetermined number of information units for recording a position information code indicating its position within the group, each recording unit within a group having an information code that differs from the information codes of every other recording unit within that group, each information unit being capable of storing first and second values;

• the information units being encoded such that:
• the position information code for any selected recording unit differs by one information unit from the position information codes for each recording unit spaced by one recording unit from the selected recording unit, and for each recording unit spaced by N-1 recording units from the selected recording unit;
• the position information code for the selected recording unit differs by two information units from the position information codes for each recording unit spaced by two recording units from the selected recording unit, and for each recording unit spaced by N-2 recording units from the selected recording unit;
• the position information code for the selected recording unit differs by at least three information units from the position information codes for each recording unit spaced by more than two and less than N-2 recording units from the selected recording unit;
• and
• at least one recording unit has a position information code including at least first, second and third information units, the second information unit being positioned between the first and third information units, said first and third information units storing the first value and the second information unit storing the second value.