This introduction to telecommunications provides a broad view of modern telecommunications principles and applications. The revised and expanded edition will meet the needs of a wider audience through the addition of more advanced material, particularly the treatment of the Fourier transform and the greater emphasis placed on the influence of noise on system performance. The book concludes with a set of case studies which illustrate the principles introduced and demonstrate their applications. There is a new case study on the Compact Disc as a communications system. In keeping with the other books in the series this book has marginal notes to expand and enrich the main text, worked examples that illustrate theory and applications, problems (with answers) graded according to difficulty at the ends of chapters and clear cross-referencing to other titles in the series where appropriate. This book should be of interest to first and second year degree and diploma courses in electrical and electronic engineering.