Four-to-six modulation code for blue laser recording channels

A highly efficient four-to-six modulation (FSM) code suitable for high density blue laser recording channels is presented. Without inserting the additional DC control bits, the low-frequency components of the FSM coded sequence can be suppressed successfully. In addition, the maximum number of repeated minimum transition that runs in the coded sequence is no more than six. The code design approach and the performances of FSM are detailed.