I am highly grateful to the editorial team of McGraw-Hill Education (India) Limited for conferring on me the honour of revising this classic textbook. The revision plan was prepared through mutual consent between Ms. Shalini Jha, Assistant Sponsoring Editor of McGraw-Hill, India and me. We had in mind the needs of the present-day students, faculty, and practising engineers while deciding on the content, presentation, and layout of the book.

I thank the editorial team of my publisher McGraw-Hill Education (India) Limited, especially, Ms. Vibha Mahajan, General Manager – Publishing, Science, Engineering & Mathematics, Technical/Vocational, Ms. Shalini Jha, Assistant Sponsoring Editor and Ms. Mini Narayanan, Copy Editor, for dealing with this book project with a concern for quality and accuracy. I am thankful to Ms. Shukti Mukherjee and Ms. Anjali Razdan for their enthusiastic cooperation. My special thanks go to Mr. Baldev Raj, Media Developer for designing the dedicated web site to this textbook. Readers can also e-mail their opinions to me at mothiki.spr@gmail.com.

I thank my colleagues in the Electronics and Communications Engineering Department who made this writing project possible with their cooperation and encouragement. My interest in this book project has been reinforced by the encouragement I received from Prof. Dharanipragada Varada Raju, Prof. Nallamothu Lakshmi Narayana, Prof. V. Ranga Rao, Prof. Pidikiti Srinivasa Rao, Prof. Alapati V.N. Tilak, and Prof. Tipirneni Venugopal and most of my colleagues and students of our college. I am indebted to Mr. Malineedu Srinivasa Rao, Ms. Kodali Sridevi, Mr. B. Rukmangada Rao and other personnel of our college library for their professional services offered under the expert guidance of our senior librarian Mr. Kanakamedala Sambasiva Rao, in effectively utilising resources like the reprographic facility, digital library, Internet, and the book reference section. I thank Mr. Potla Nageswara Rao, Secretary and Correspondent, and Prof Nutakki Nageswara Rao, Principal of Adam’s Engineering College for their cooperation and support.

I have to admit that I could not have transformed this book into the present form without the love and participation of my sons—Vamsi Krishna and Sasikanth. I thank my wife Saraswathi for helping to sustain my interest in the book project with her smiling face and several cups of South Indian coffee.

Mothiki S. Prakash Rao