With the advent of high‐speed logic circuits and very large scale integration, data processing and storage equipment has inexorably moving towards digital techniques. In digital systems, data are encoded into strings of zeros and ones, corresponding to the on and off states of semiconductor switches. The migration of analog communications to the now ubiquitous digital forms of communications is enabled primarily by the fast‐paced advances in high‐density device integration. While straightforward miniaturization of the CMOs (complementary metal–oxide–semiconductor) devices is becoming increasingly more difficult, transistor designers have been very creative in modifying the designs to stay on the Moore trajectory. The migration from analog to digital information processing has opened the door for many sophisticated algorithmic methods. The chapter incorporates modern digital communication and its brief history, error control coding bandwidth, power, and complexity. The migration from analog to digital information processing has opened the door for many sophisticated algorithmic methods.