Data encoding method and system employing two-thirds code rate with full word look-ahead

摘要

A method and apparatus for encoding binary data in a data stream so as to increase the number of data bits represented by one transition, such as a transition recorded on a magnetic medium, and thereby increase the storage density. The data stream is converted into words each having m bits. Two of the data words are stored so as to be simultaneously accessible to a converting system that converts the data words into code words wherein each code word has n bits. In the invention, m/n=2/3. In order to increase the space between adjacent transitions, the conversion is carried out according to a scheme wherein all code words have at least one binary ONE and lack successive binary ONEs except certain cases in which a code word is converted to all ZEROs to avoid ONEs in the nth bit of a given code word and the first bit of the code word following the given code word. Also described is a decoding method and apparatus for recovering the encoded data and decoding it to the original binary data.