Finite-state machine RLL coding with limited repeated minimum transition runlengths

摘要

For deriving a repeated minimum transition run (RMTR) limitation compliant channel code and decoder from a given state transition diagram of an original code that is finite state machine (FSM) decodable, run-length limited (RLL) and has no repeated minimum transition run (RMTR) limitation, the invention proposes to identify, as RMTR violating loops, state transitions causing unlimited repeated minimum runs, which state transition are represented in the state transition diagram by closed loops; to break the identified RMTR violating loops by inserting an additional state into the diagram and by re-directing violating transitions; and to assign valid next state/output codeword pairs to the inserted state for each possibility of re-directing violating transitions. The invention describes steps which guarantee that the resulting RLL code fulfills the d-constraint of the original code, is RMTR limited, and remains decodable.