Patent attributes
An encoder encodes data into parallel codewords. Each codeword is expressed as a set of logic 0s and a set of logic 1s on two sets of output nodes. The encoder selects a current codeword which differs from the immediately preceding codeword by a fixed number of zero-to-one transitions on the first set of nodes and a fixed number of one-to-zero transitions on the second set of nodes. The current codeword is selected such that the first and second sets of nodes are different than additional nodes that contain transitions between the immediately preceding codeword and a bi-preceding codeword, and that logic values on additional nodes are unchanged between immediately preceding codeword and current codeword. A decoder decodes the codewords by comparing symbols on node pairs other than those for which transitions were expressed in the preceding code word, and decoding the results of those comparisons.
