Two techniques for constructing DC-free codes with minimum distance 4

Two techniques for constructing DC-free codes with minimum distance 4 are presented. These constructions result in very low complexity implementation and allow both hard and soft decision decoding to be applied. Construction 1 is based on adapting an algorithm developed for constructing a class of low complexity runlength limited error control codes having a maximum runlength constraint of 6 and minimum distance 4. Construction 2 is based on utilising simple array codes based on two parity check codes and mapping balanced words onto each row of the array (the same mapping being applied to every row) in place of the even parity word.<>