Digital communications is the foundation of modern telecommunications and digital signal processing. The second edition of Digital Communications is updated to include current techniques and systems used in the rapidly expanding field of fixed and mobile communications. The text has comprehensive coverage of digital communications without going into unnecessary detail or irrelevant topics. Its main aims are to develop the mathematical theory behind signal processing and use this knowledge to develop fixed and mobile data communications systems. This text is geared towards students who already have a technical understanding of electrical engineering from their introductory years at university and who wish to focus on digital communications. It covers everything these students will need to know, including modern techniques.