Patent ID: 6653952
Filing Date: 2003-11-25
Classification: G11B,H03M

Abstract:
A modulation method comprising:referring to a plurality of coding tables each including output code words corresponding to input data words, and coding table designation information in which a coding table for use in encoding a next input data word is designated, to thereby encode a four bit unit of a plurality of continuous input data words into a six bit unit of a plurality of continuous output code words, said plurality of coding tables including at least a first coding table and a second coding table, first and second signals being reverse to each other in polarity, the first and second signals being respectively obtained by subjecting a first output code word of said first coding table corresponding to a predetermined input data word and a second output code word of said second coding table corresponding to said predetermined input data word to NRZI modulation: and inserting two redundant bits into said plurality of continuous output code words for each predetermined number of corresponding data words, so that a digital sum variation (DSV) control is performed in any section irrespective of the redundant bits, k satisfies 9 in a (1, k) run length limited (RLL) rule, and a successive repetition frequency of a minimum run is limited.