MODULATOR, MODULATION METHOD AND SERVING MEDIUM

摘要

PROBLEM TO BE SOLVED: To conduct DSV control in a data string and with few redundancies. SOLUTION: A bit insert section 21 inserts DSV control bits with a level '0' to a received data string at a prescribed interval for producing a first data string, and inserts DSV control bits with a level '1' to the received data string at a prescribed interval to produce a second data string. A modulation and NRZI processing section 22 conducts modulation and NRZI processing for the two sets of the data strings. A DSV calculation block extract section 23 extracts each DSV calculation block and a block DSV calculation section 25 calculates each block DSV in the extracted block. An accumulation DSV calculation and DSV bit decision section 26 sums respectively DSV accumulated thus far and blocks DSV of the first or 2nd data strings, and allows a DSV control data string decision section 24 to select and output either of the DSVs with smaller absolute sum.