Digital Communications is the result of the author’s 38 years’ experience in teaching, and in design and development of various wireless communication systems. It covers all primary areas in digital communication systems in engineering. The book intends to give the students a grasp of the basic issues of communication systems during transition from analog to digital. To make the reading interesting as well as systematic, conscious efforts have been made to explain the basics of technology, avoiding complex mathematics as far as possible. Numerical problems are then introduced to help the students fully understand the concepts and applications.