PURPOSE: To increase the suppression effect of a spectrum even at a low frequency area by using a code word only in which consecutive number of same signal levels is 4 or below after NRZI modulation and whose CDS is ±1, suppressing the divergence of the DSV according to a DSV control signal thereby coding the CDS value.
CONSTITUTION: An 8-bit information word is inputted to a coder 13 and a DSV control signal is inputted to a code selector 14. The selector 14 outputs inverting number information quantity and a table selection signal Q' of a code word after the code word is subject to NRZI modulation to the coder 13. The code word from the coder 13 is inputted to a converter 15, in which the parallel code word is converted into a serial code and the result is inputted to a modulator 16, in which the code word is subject to NRZI conversion and the result is outputted.
IDO KIHEI
KOSAKA HIDEAKI
