This textbook will provide both undergraduates and practising engineers with an up-to-date and thorough grounding in the concepts of modern digital transmission. The book is not encyclopaedic, rather it selects the key concepts and processes and explains them in a deliberate pedagogic style. These concepts and processes are then illustrated by a number of system descriptions. The book is divided into three parts. The longest, Part II, describes the basic processes of digital transmission, such as matched filter detection, pulse shaping, line coding, channel coding, error detection and correction, etc. Understanding the concepts behind these processes requires a grasp of basic mathematical models, and this is provided in Part I. Finally, to put the processes in context, Part III describes elements of the public switched telephone network. The text is written throughout in a modern, digital context, and is comprehensively illustrated with helpful figures. Although the mathematical models