Method and device for code modulation, method and device for code demodulation, and method and device for decoding

A code modulation device for converting a 16-bit data to a 20-bit code comprising

• receiving means for receiving said 16-bit data, and
• generation means for generating said 20-bit code corresponding to said 16-bit data,
• said 20-bit code being a code generated according to the state transition diagram composed of P.times.Q states,
• in said state transition diagram, P.times.Q states being arranged on the space having the first axis and second axis, a code of 00 being assigned when the state transits from a certain said state to another said state along said first axis in the first direction,
• a code of 11 being assigned when the state transits from a certain said state to another said state along the first axis in the second direction opposite to said first direction,
• a code of 01 being assigned when the state transits from a certain said state to another said state along said second axis in the third direction,
• a code of 10 being assigned when the state transits from a certain said state to another said state along said second axis in the fourth direction opposite to said third direction, and
• said 20-bit code comprising the combination of codes respectively assigned to the transition of said states.

A code demodulation method for converting a 20-bit code to 16-bit data comprising the first step for receiving said 20-bit code and the second step for generating 16-bit data corresponding to said 20-bit code,

• said 20-bit code being any one of codes generated according to the state transition diagram composed of P.times.Q states,
• in said state transition diagram, P.times.Q states being arranged on the space having the first axis and second axis, a code of 00 being assigned when the state transits from a certain said state to another said state along said first axis in the first direction,
• a code of 11 being assigned when the state transits from a certain said state to another said state along the first axis in the second direction opposite to said first direction, the code of 01 being assigned when the state transits from a certain said state to another said state along said second axis in the third direction,
• a code of 10 being assigned when the state transits from a certain said state to another said state along said second axis in the fourth direction opposite to said third direction, and
• said 20-bit code comprising the combination of codes respectively assigned to the transition of said states.

A code demodulation device for converting a 20-bit code to 16-bit data comprising a means for receiving said 20-bit code and a generation means for generating 16-bit data corresponding to said 20-bit code,

• said 20-bit code being any one of codes generated according to the state transition diagram composed of P.times.Q states,
• in said state transition diagram, P.times.Q states being arranged on the space having the first axis and second axis, a code of 00 being assigned when the state transits from a certain said state to another said state along said first axis in the first direction,
• a code of 11 being assigned when the state transits from a certain said state to another said state along the first axis in the second direction opposite to said first direction, a code of 01 being assigned when the state transits from a certain said state to another said state along said second axis in.the third direction,
• a code of 10 being assigned when the state transits from a certain said state to another said state along said second axis in the fourth direction opposite to said third direction, and
• said 20-bit code comprising the combination of codes respectively assigned to the transition of said states.

A code decoding method wherein said code decoding method comprises,

• the first step for receiving a supplied 20-bit code, said 20-bit code is a code generated according to the state transition diagram composed of P.times.Q (both P and Q are positive integers) states, in said state transition diagram, P.times.Q states are arranged on the space having the first axis and second axis, a code of 00 is assigned when the state transits from a certain said state to another said state along said first axis in the first direction, a code of 11 is assigned when the state transits from a certain said state to another said state along the first axis in the second direction opposite to said first direction, a code of 01 is assigned when the state transits from a certain said state to another said state along said second axis in the third direction, a code of 10 is assigned when the state transits from a certain said state to another said state along said second axis in the fourth direction opposite to said third direction, and said 20-bit code comprises the combination of codes respectively assigned to the transition of said states,
• the second step for providing inter-code interference due to partial response (1,1) characteristics, and the third step for decoding the 20-bit code provided with said inter-code interference in said second step using Viterbi decoding,
• wherein in said third step,
• said Viterbi decoding is performed according to the state transition diagram composed of 2.times.Q states,
• in said state transition diagram, 2.times.Q demodulation states are arranged along the third axis and forth axis,
• the code of 00 is generated when the state transits from a certain demodulation state to another demodulation state along said third axis in the fifth direction and the sampling value of 0-1 is supplied,
• the code of 11 is generated when the state transits from a certain demodulation state to another demodulation state along said third axis in the sixth direction opposite to said fifth direction and the sampling value of 0+1 is supplied,
• the code of 01 is generated when the state transits from ascertain demodulation state to another demodulation state along said fourth axis in the seventh direction and the sampling value of 00 is supplied,
• the code of 10 is generated when the state transits from a certain demodulation state to another demodulation state along said fourth axis in the eighth direction opposite to said seventh direction and the sampling value of 00 is supplied,
• the code of 10 is generated when the state transits from a certain demodulation state to another demodulation state in the ninth direction along said sixth axis intersecting said third axis and fourth axis and the sampling value of +10 is supplied,
• the code of 01 is generated when the state transits from a certain demodulation state to another demodulation state in the tenth direction opposite to said ninth direction along said sixth axis and the sampling value of -10 is supplied, the code of 00 is generated when the state transits from the demodulation state disposed in the fifth direction to the demodulation state and the sampling value of -1-1 is supplied in the demodulation state arranged in a form of a pair in said fifth direction and sixth direction, and
• the code of 11 is generated when the state transits from the demodulation state disposed in the sixth direction to the demodulation state and the sampling value of 11 is supplied in the demodulation state arranged in a form of a pair in said fifth direction and sixth direction.

A code decoding device wherein said code decoding device comprises,

• means for receiving a supplied 20-bit code, said 20 bit code is a code generated according to the state transition diagram comprising P.times.Q (both P and Q are positive integers) states, in said state transition diagram, P.times.Q states are arranged on the space having the first axis and second axis, a code of 00 is as signed when the state transits from a certain said state to another said state along said first axis in the first direction, a code of 11 is assigned when the state transits from a certain said state to another said state along the first axis in the second direction opposite to said first direction, a code of 01 is assigned when the state transits from a certain said state to another said state along said second axis in the third direction, a code of 10 is assigned when the state transits from a certain said state to another said state along said second axis in the fourth direction opposite to said third direction, and said 20-bit code comprises the combination of codes respectively assigned to the transition of said states,
• means for providing inter-code interference due to partial response (1, 1) characteristics, and
• decoding means for decoding the 20-bit code provided with said inter-code interference by said inter-code interference means using Viterbi decoding,
• wherein in said decoding means,
• said Viterbi decoding is performed according to the state transition diagram composed of 2.times.Q states,
• in said state transition diagram, 2.times.Q demodulation states are arranged along the third axis and forth axis,
• the code of 00 is generated when the state transits from a certain demodulation state to another demodulation state along said third axis in the fifth direction and the sampling value of 0-1 is supplied,
• the code of 11 is generated when the state transits from a certain demodulation state to another demodulation state along said third axis in the sixth direction opposite to said fifth direction and the sampling value of 0+1 is supplied,
• the code of 01 is generated when the state transits from a certain demodulation state to another demodulation state along said fourth axis in the seventh direction and the sampling value of 00 is supplied,
• the code of 10 is generated when the state transits from a certain demodulation state to another demodulation state along said fourth axis in the eighth direction opposite to said seventh direction and the sampling value of 00 is supplied,
• the code of 10 is generated when the state transits from a certain demodulation state to another demodulation state in the ninth direction along said sixth axis intersecting said third axis and fourth axis and the sampling value of +10 is supplied,
• the code of 0 1 is generated when the state transits from a certain demodulation state to another demodulation state in the tenth direction opposite to said ninth direction along said sixth axis and the sampling value of -10 is supplied, the code of 00 is generated when the state transits from the demodulation state disposed in the fifth direction to the demodulation state and the sampling value of -1-1 is supplied in the demodulation state arranged in a form of a pair in said fifth direction and sixth direction, and
• the code of 11 is generated when the state transits from the demodulation state disposed in the sixth direction to the demodulation state and the sampling value of 11 is supplied in the demodulation state arranged in a form of a pair in said fifth direction and sixth direction.