Data modulation method

摘要

In a data modulation method, m-bit data is modulated to n-bit data (n>/=m) having fewer direct current and low frequency components. A dispersion of the digital sum variation of code weights can be reduced, a direct current component is reduced and an error rate can be further reduced by selecting a plurality of modulation tables constituting the combination of one or more sub-groups of modulation data obtained by dividing a group of modulation data by a code weight having the same value based on the digital sum variation of the code weights accumulated until a time at which m-bit data is converted to n-bit code and converting next m-bit data continuously to present m-bit data to n-bit code by using the modulation tables.