A method for constructing a DC free recording code and an example of its application

This paper presents a new method for systematically constructing DC free binary recording code which may be categorized into a sliding block code. The DC free recording coded sequence corresponding to magnetic recording waveform is generated by applying the two level finite sequential machine which has the structure given by the loop-sum-zero transition diagram. As an example of the application of this method, we present a new DC free recording code where the minimum and maximum intervals in which magnetic transitions occur in the recording waveform are 1.25 times and 2.5 times larger, respectively, than the unit interval of the data sequence. The main advantages of this recording code are briefly described.