A Delta-Sigma (дс) Modulator is a relatively simple system, which, however, has attracted the interest of many and very important research workers and professionals over the past 40 and more years. It is an academically challenging system, because it involves analog and/or digital issues for its study and implementation. Most important though is the practical aspect of it, because of its robustness and the number of important applications among which its use in the design of Analog-to-Digital Converters and Digital-to-Analog Converters predominates. A great number of research and tutorial papers as well as excellent books have been published. Although the topic of дс Modulation has undoubtedly reached a considerably high state of maturity, the literature nevertheless continues to be enriched with new and scientifically sound contributions to this topic.

The extended literature on дс modulation has been one of the main reasons behind the decision of these authors to write this book. They felt the need to assist the newcomer professional, the advanced final year First Degree in Electrical Engineering students and early postgraduate students in getting easier involved with this topic. The book covers the most important issues associated with the study, design and implementation as well as some important applications of дс modulators.

The content of the book refers nearly exclusively to all issues applied to single-bit, single-stage дс modulators for reasons of simplicity in the presentation and design popularity. Oversampling and noise shaping, noise modeling, system architectures, noise transfer function derivation, stability considerations, design implementation and practical imperfections, stabilization techniques, application of дс modulation to the design of data converters, frequency synthesis etc. are the main issues examined to some detail. Moreover the issue of low power systems is explained briefly. Practical design examples are given for those readers who would be interested in reproducing in their laboratory the designed circuits using discrete components. These include low-pass and band-pass single-bit дс modulators.

It has been attempted to make the book educationally rather than research oriented. A number of solved examples have been included in the text, where it was felt necessary, while unsolved problems can be found at the end of each chapter. Extended bibliography is also given at the end of each chapter to help the interested reader get a deeper understanding of the various issues described in the text. Finally, a web site has been built relevant to the book with the purpose of bringing the authors and the reader in close contact. The visitor to the site will find information about the book, possible misprint corrections, solutions to the unsolved problems etc. in the following address:

Preparing a manuscript is not an easy task, especially when the authors belong to three different generations as these authors do. However, the fact that the three younger ones had been both undergraduate and postgraduate students of the eldest (T. Deliyannis), coupled with the traditional respect that well brought-up Greek students feel towards their seniors, simplified this task.

Therefore, the completion of the manuscript was achieved in an amicable and co-operative atmosphere. It is with great pleasure that the senior author acknowledges the important contribution of each one of his co-authors in preparing the manuscript and expresses his gratitude to them for offering him the satisfaction of terminating his official university career in coincidence with the publication of this book. He also expresses his thanks to A. Doyle and Yeow-Hwa-Quek for making all necessary arrangements for the publication of the book as well as to Professor A.G. Constantinidis of Imperial College, London for many useful discussions and his encouragement. Drs N. Kouvaras and D. Lagoyiannis are gratefully acknowledged for their earlier collaboration with this author in Delta Modulation and for their assistance in his research in the subject of the book.Thanks are also due to V. Boile for typing chapter 1 and other minor parts of the manuscript. The married authors (T.D, V.A. and A.P.) express their thanks to their spouses Myriam, Maria and Efi respectively for their patience and understanding, particularly when many professional and personal needs had to be left aside in order to give priority to the preparation of some urgent parts of the manuscript. The other author (G.B.) thanks his parents for their love and understanding.

GB Patras
AP Athens
VA Patras
TLD Patras