PURPOSE: To obtain an excellent DC free code by making a unique rule to the number of consecutive bits of "0" or "1" at at both right and left ends of a channel code word and the corresponding relation of connecting conditions or the like among the channel code words when the number of minimum consecutive bits capable of maximizing a detected window width TW is "1".
CONSTITUTION: Channel code words CW0, CW0', CW1∼CW3, their disperity DP and an F value being 0 when the left side L is K-K' and 1 when not are stored in an ROM(101). A channel code word CW4, its DP and F values are stored in an ROM(102). After N-bit of outputs from the ROMs (101) and (102) is fed to P-S converters 103, 106 and converted into a serial signal, the signal is fed to a multiplexer 105 directly or through inverters 104, 107. Moreover, a multiplexer 105 is controlled based on the final bit LB of the code word transmitted to a channel before a preceding time and a digital sum variation.
YAMAMITSU CHIYOUJIYUROU
SUESADA KUNIO
OGURA ICHIROU
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