On DC free magnetic recording codes generated by finite state machines

State systems for the encoding of the following magnetic recording codes, with minimum Hamming distance d
min
, as indicated, are presented. A R = ½, (1, 4, 3), d
min
= 2 code; a R = ½, (0, 3, 3), d
min
= 4 code; and a R = 2/4, (0, 3, 2), d
min
= 4 code. An encoder and decoder for the (1, 4, 3) code are shown. Minimum Hamming distance aspects of dc free codes, generated by finite state machines, are briefly discussed.