DATA MODULATION METHOD CAPABLE OF SUPPRESSING DC BY USING PARITY INFORMATION OF SYNCHRONOUS CODEWORD AND DEVICE THEREOF, CONCERNED WITH SUPPRESSING DC COMPONENTS OF CODEWORD STREAM WITHOUT DETERIORATING CODE RATE

摘要

PURPOSE: A data modulation device capable of suppressing a DC(Direct Current) by using parity information of a synchronous codeword is provided to set a bit for controlling a parity within a synchronous codeword, so that the parity of the synchronous codeword can multiplex input data according to an even number or an odd number, thereby effectively suppressing DC components of a codeword stream without deteriorating a code rate. CONSTITUTION: A multiplexer(20) attaches 1-bit multiplexing information to each data string divided by a divider(10), multiplexes into 2 data strings, and converts it into 2 kinds of pseudo random data according to the information. The first and second synchronous/multiplexing ID inserters(31,32) of a synchronous codeword inserter(30) insert synchronous codewords into the pseudo random data. An encoder(40) generates codewords during an insufficient DC suppression RLL(Run Length Limited) modulation, groups the codewords, and performs the RLL modulation. A comparator/selector(50) compares modulation streams of 2 channels, and selects a modulation stream having small DC components.