A METHOD AND APPARATUS FOR PRODUCING A DC BALANCED (0,4) RUN LENGTH LIMITED RATE 8B/10B CODE FROM AN INPUT DATA STREAM

摘要

A binary DC balanced code and an encoder circuit for effecting same is described, which translates an 8 bit byte of information into 10 binary digits for transmission over electromagnetic or optical transmission lines subject to timing and low frequency constraints. The significance of this code is that it combines a low circuit count for implementation with excellent performance near the theoretical limits, when measured with the commonly accepted criteria. The 8B/10B coder is partitioned into a 5B/6B plus a 3B/4B coder. The input code points are assigned to the output code points so the number of bit changes required for translation is minimized and can be grouped into a few classes.