Multilevel Balanced Code with Redundant Digits

In this concise paper, several coding schemes are proposed for transmitting digital information over a cable with dc cutoff. The codes are composed of information digits and balance digits determined by the weight of the former. It is shown that the encoding and decoding circuits are quite simple, and that the dc component of the codes is negligibly small. Furthermore, the lowfrequency components of the spectrum can be made much smaller by changing the balance digit positions. Exploiting the fact that the weight of almost all codes is zero, and using the coding rule presented, block synchronization can be easily obtained and most transmission errors can be detected.