High-rate DC-free ternary runlength-limited codes

DC-free codes are useful on all fiber channels, on ADSL (asymmetric digital subscriber line) and SDH (synchronous digital hierarchy) systems (Alexandru and Kim, 2003). RLL (run-length-limited) codes facilitate the synchronization process of the data receiver and establish a balanced use of the transmitter equipment (Schouhamer et al., 1998). The binary-to-ternary coding method increases the transmission rate and the sliding-window decoders ensure small error-propagation. All these advantages are combined into the optimum ternary RLL codes presented in this paper. Some new ternary RLL codes are designed based on a simplified method (Seripearu and Duma, 2003).