An 8-15 Modulation Method Suitable for High Density Digital Recording

Previously we proposed a DC component suppressing method which adds an extra one-byte data to a data block of fixed bytes and converts information data into channel codewords. In this paper, we propose 8-15 channel coding which has no DC component suppressing capability, and 8-15 modulation method which is based on 8-15 channel coding and DC component suppressing method. The window margin and the minimum interval between transitions of the 8-15 channel data are about 6.6% longer than those of (2, 7) RLL codes, and are theoretically the most suitable length when 8-bit data words are translated into 15-bit codewords. The 8-15 modulation method is superior to the (2, 7) RLL coding in respect to some of their characteristic parameters and suppresses low-frequency components efficiently.