Signal error-correction system and method

An encoder for generating a 9-bit codeword representative of an 8-bit byte of information, comprising:

• (a) an input which receives an 8-bit byte of a digital input signal;
• and
• (b) selective codeword means, operatively coupled to the input, for generating selected codewords of 2.sup.9 (512) possible 9-bit codeword signals that can be 1:1 mapped to 2.sup.8 (256) possible 8-bit bytes of the digital input signal, the selected codewords not including any of the possible 9-bit codewords having any undesirable characteristics, these undesirable include having:
• (i) any sequence of 4 consecutive transitions occurs therein, (ii) an ending sequence of 2 or more consecutive transitions, (iii) a beginning sequence of more than 2 consecutive transitions, and (iv) a sequence of 3 consecutive transitions begins on a 1st, 3rd, 5th, 7th, or 8th bit of the codeword signal.

A decoder for generating an estimated 8-bit byte of information representative of a 9-bit codeword, comprising:

• (a) an input which receives an 9-bit codeword signal;
• and
• (b) decoder means, operatively coupled to the input, for estimating 8-bit bytes from the 9-bit codeword signal based on selected codewords of 2.sup.9 (512) possible 9-bit codeword signals that can be 1:1 mapped from 2.sup.8 (256) possible 8-bit information signals, the selected codewords being constrained to not included any of the possible 9-bit codewords having any undesirable characteristics, these undesirable include having:
• (i) any sequence of 4 consecutive transitions occurs therein, (ii) an ending sequence of 2 or more consecutive transitions, (iii) a beginning sequence of more than 2 consecutive transitions, and (iv) a sequence of 3 consecutive transitions begins on a 1st, 3rd, 5th, 7th, or 8th bit of the codeword signal.

A method of encoding a digital data signal in computer-readable form which has been embodied in a tangible medium of information storage, in accordance with the following steps:

• (a) encoding an 8-bit type of digital input signal to provide a 9-bit codeword signal such that:
• (i) no sequence of 4 consecutive transitions occurs in said 9-bit codeword signal, (ii) said 9-bit codeword signal does not end with a sequence of 2 or more consecutive transitions, (iii) said 9-bit codeword signal does not begin with more than 2 consecutive transitions, and (iv) sequences of 3 consecutive transitions, if any, begin only on a 2nd, 4th, 6th, or 9th-bit codeword signal;
• (b) serializing said 9-bit codeword, whereby a serialized subsequence signal is provided;
• (c) precoding said serialized subsequence signal by subjecting it to a transfer function 1/(1.sym.D), whereby a precoded serialized signal is provided;
• and
• (d) equalizing said precoded serialized signal thereafter has been transmitted to the receiving signal such that, when the coded serialized signal thereafter has been transmitted to the receiving location form the point of transmission, the precoded serialized signal will have been subjected to an effective transfer function of (1-D)(1+D).sup.2 for EPR4 or to an effective transfer function of (1-D)(1+D).sup.3 for E.sup.2 PR4.

A method of transmitting intelligible information to a receiving location distanced from a point of transmission, said method comprising transmitting from the point of transmission to the receiving location electromagnetic radiation carrying information encoded onto the electromagnetic radiation in accordance with the following coding steps:

• (a) encoding an 8-bit byte of digital input signal to provide a 9-bit codeword signal such that:
• (i) no sequence of 4 consecutive transitions occurs in said 9-bit codeword signal, (ii) said 9-bit codeword signal does not end with a sequence of 2 or more consecutive transitions, (iii) said 9-bit codeword signal does not begin with more than 2 consecutive transitions, and (iv) sequences of 3 consecutive transitions, if any, begin only on a 2nd, 4th, 6th, or 9th bit of said 9-bit codeword signal;
• (b) serializing said 9-bit codeword signal, whereby a serialized subsequence signal is provided;
• (c) precoding said serialized subsequence signal by subjecting it to a transfer function 1/(1.sym.D), whereby a precoded serialized signal is provided;
• and
• (d) equalizing said precoded serialized signal to provide a coded serialized signal such that, when the coded serialized signal thereafter has been transmitted to the receiving location from the point of transmission, the precoded serialized signal will have been subjected to an effective transfer function of(1-D)(1+D).sup.2 for EPR4 or to an effective transfer function of (1-D)(1+D).sup.3 for E.sup.2 PR4.