8-bit data word to 15-bit codeword converter utilizing periodically varying digital sum variation

摘要

A plurality of first codeword pairs each including a 15-bit codeword of which CDS is equal to +3 and a 15-bit codeword of which CDS is equal to -1 and a plurality of second code pairs each including a 15- bit codeword of which CDS is equal to +1 and a 15-bit codeword of which CDS is equal to -3 are produced. One of the plurality of first code pairs and one of the plurality of second code pairs are assigned to each 8-bit data word, and one of the first and second code pairs assigned to each 8- bit data word is selected so that the number of continuous identical bits in a 15-bit codeword sequence is not less than 2 and not more than 8. One of two 15-bit codewords included in the selected code pair is selected so that DSV at the last bit of each 15-bit codeword periodically varies.