Method and apparatus for encoding MB810 line code with the characteristics of minimum bandwidth and DC-free

A method for converting m-bit input data into an n-bit codeword, comprising:

• receiving input data and generating a serial data stream, the serial data stream having frame-word for synchronization;
• converting the serial data stream into a parallel data stream;
• storing a plurality of codewords and a plurality of input date into an encoding table, the codewords being obtained by:
• selecting the number of input bits m and the number of output bits n for an (m,n) block code;
• accumulating a sufficient number of BUDA (binary unit DSV and ASV) cells to form a BUDA stack for derivation of a state diagram;
• picking one node as a state, and securing at least 2m exit paths of an n-hop length, and denoting each terminating node of each path as another state;
• starting with a new state and repeating previous step;
• if it turns out that the stack needs to be expanded to complete the state diagram, adding more cells to the stack either horizontally or vertically as appropriate;
• reducing the number of states as possible with all transition paths terminating on one of the arranged states;
• at each state, arranging the mapping table as an input m-bit combination to an output n-bit combination;
• and,
• as necessary, plotting the power spectrum of the coded sequence with varying input bit probability, and choosing the mapping that would generate the most desirable power spectral properties;
• looking up said encoding table and searching for a parallel codeword, and pairing the parallel codeword with the input data;
• and
• converting the parallel codeword into a serial codeword.

A method for converting an n-bit codeword into anx m-bit input data, comprising:

• recovering a system clock signal and latching a serial codeword;
• generating an enable signal when a frame-word codeword is detected from the serial codeword;
• converting the serial codeword into a parallel codeword when the enable signal is generated;
• storing a plurality of codewords and a plurality of input data in a decoding table, the codewords being obtained by:
• selecting the number of input bits m and the number of output bits n for an (m,n) block code;
• accumulating a sufficient number of BUDA (binary unit DSV and ASV) cells to from a BUDA stack for derivation of a state diagram;
• picking one node as a state, and securing at least 2m exit paths of an n-hop length, and denoting each terminating node of each path as another state;
• starting with a new state and repeating previous step;
• if it turns out that the stack needs to be expanded to complete the state diagram, adding more cells to the stack either horizontally or vertically as appropriate;
• reducing the number of states as possible with all transition paths terminating on one of the arranged states;
• at each state, arranging the mapping table as an input m-bit combination to an output n-bit combination;
• and,
• as necessary, plotting the power spectrum of the coded sequence with varying input bit probability, and choosing the mapping that would generate the most desirable power spectral properties;
• receiving said parallel codeword and looking up a decoding table to search for a parallel data stream, and pairing the parallel data stream with the parallel codeword;
• converting the parallel data stream into a serial data stream;
• and
• receiving the serial data stream, detecting a frame-word, and generating an input data stream.