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T L Singal is currently Professor in the Department of Electronics and Communication Engineering, Chitkara University, Chandigarh. He graduated in Electronics and Communication Engineering from National Institute of Technology (NIT), Kurukshetra, and post-graduated in Electronics and Communication Engineering from Punjab Technical University, Jalandhar. He has worked in the field of Wireless and Cellular Communications with leading telecom organisations in India and USA during 1981–2002 and has managed various VHF/UHF Wireless Communication Projects in reputed companies like HAL, Hyderabad, and PSIDC, Chandigarh. He visited Germany on business trips for technical expertise transfer of Multi-Access Wireless Communication Systems during 1990–92. In his association with Flextronics International Inc., Dallas (Texas), USA, he held the position of Senior Network Consultant, offering optimization solutions in the domain of GSM, and CDMA cellular networks for various clients such as Nokia, AT&T, Nortel, Cingular Wireless, Voice Stream USA during 2000–2002. Since 2003, he has been working with leading engineering institutes in India as Senior Faculty of Electronics and Communication Engineering. Prof. Singal’s areas of interests include modelling and performance analysis of digital communication systems, seamless mobility in future-generation digital cellular networks, and convergence of wireless and Internet technologies. He has convened international conferences and workshops on wireless networks and embedded systems, and edited proceedings of conferences. He has presented several technical research papers in international journals and conferences. He is also the author of a textbook titled Wireless Communications, published by Tata McGraw-Hill Education in the year 2010. T L Singal Professor Department of Electronics and Communication Engineering Chitkara University Chandigarh Tata McGraw Hill Education Private Limited NEW DELHI McGraw-Hill Ofﬁ ces New Delhi New York St Louis San Francisco Auckland Bogotá Caracas Kuala Lumpur Lisbon London Madrid Mexico City Milan Montreal San Juan Santiago Singapore Sydney Tokyo Toronto Tata McGraw-Hill Published by Tata McGraw Hill Education Private Limited, 7 West Patel Nagar, New Delhi 110 008. Analog and Digital Communications Copyright © 2012 by Tata McGraw Hill Education Private Limited No part of this publication may be reproduced or distributed in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise or stored in a database or retrieval system without the prior written permission of the publishers. The program listings (if any) may be entered, stored and executed in a computer system, but they may not be reproduced for publication. This edition can be exported from India only by the publishers, Tata McGraw Hill Education Private Limited. ISBN (13): 978-0-07-107269-4 ISBN (10): 0-07-107269-1 Vice President and Managing Director—MHE: Ajay Shukla Head—Higher Education Publishing and Marketing: Vibha Mahajan Publishing Manager (SEM & Tech. Ed.): Shalini Jha Editorial Executive: Koyel Ghosh Executive—Editorial Services: Sohini Mukherjee Senior Production Managers: Satinder S Baveja, P L Pandita Marketing Manager—Higher Education: Vijay Sarathi Sr. Product Specialist—Tina Jajoria General Manager—Production: Rajender P Ghansela Manager—Production: Reji Kumar Information contained in this work has been obtained by Tata McGraw-Hill, from sources believed to be reliable. However, neither Tata McGraw-Hill nor its authors guarantee the accuracy or completeness of any information published herein, and neither Tata McGraw-Hill nor its authors shall be responsible for any errors, omissions, or damages arising out of use of this information. This work is published with the understanding that Tata McGraw-Hill and its authors are supplying information but are not attempting to render engineering or other professional services. If such services are required, the assistance of an appropriate professional should be sought. Typeset at Bharati Composers, D-6/159, Sector-VI, Rohini, Delhi 110 085, and printed at Rajkamal Electric Press, Plot No 2, Phase-IV, HSIIDC, Kundli, Sonepat, Haryana 131 028 Cover: Rajkamal Electric Press RQXYYRXDHZDYY The McGraw-Hill Companies Dedicated To My Spiritual Guruji—Rishi Keshva Nand ji Maharaj and My Parents—Shri Kali Ram and Shrimati Kaushalya Devi Singal Preface xv Acknowledgements xix List of Important Symbols xxi 1.1 Historical Perspective 1 1.2 Electromagnetic Frequency Spectrum 2 1.3 Signal and its Representation 4 1.4 Elements of Electronic Communications System 13 1.5 Primary Communication Resources 14 1.6 Signal Transmission Concepts 17 1.7 Analog and Digital Transmission 19 1.8 Modulation 25 1.9 Concept of Frequency Translation 29 1.10 Signal Radiation and Propagation 31 Advance-Level Solved Examples 42 Chapter Outcomes 45 Important Equations 45 Key Terms with Definitions 46 Objective Type Questions with Answers 47 Multiple Choice Questions 52 Review Questions 54 Analytical Problems 55 MATLAB Simulation Examples 58 Introduction 65 2.1 Classification of Signals and Systems 65 2.2 Review of the Fourier Series 72 2.3 Convolution and Correlation 78 2.4 Power Signal and Spectral Representation 82 2.5 Complex Waves 87 2.6 The Sampling Function 87 2.7 Parseval’s Theorem 88 2.8 Geometric Representation of Signals 91 2.9 Signal Transmission Through Linear System 93 2.10 Random Variables 95 2.11 Probability Distributions 101 2.12 Central Limit Theorem 105 2.13 Random Processes 107 Advance-Level Solved Examples 111 Chapter Outcomes 113 Important Equations 114 Key Terms with Definitions 114 Objective Type Questions with Answers 116 Multiple Choice Questions 119 Review Questions 122 Analytical Problems 123 MATLAB Simulation Examples 127 Introduction 136 3.1 Classification and Sources of Noise 136 3.2 Frequency-Domain Representation of Noise 143 3.3 Representation of Narrowband Noise 145 3.4 Linear RC Filtering of Noise 148 3.5 Signal-to-Noise Ratio (SNR) 155 3.6 Noise Analysis and Measurements 156 3.7 Equivalent Noise Bandwidth 158 3.8 Equivalent Noise Temperature 160 3.9 Noise Figure 161 Advance-Level Solved Examples 168 Chapter Outcomes 171 Important Equations 171 Key Terms with Definitions 171 Objective Type Questions with Answers 172 Multiple Choice Questions 177 Review Questions 179 Analytical Problems 180 MATLAB Simulation Examples 186 4.1 Types of Analog Modulation 189 4.2 Principles of Amplitude Modulation 190 4.3 AM for a Complex Modulating Signal 203 4.4 AM Power Distribution 206 4.5 AM Current Distribution 211 4.6 Limitations of AM 213 4.7 DSBSC Modulation Technique 214 4.8 SSB Modulation Technique 217 4.9 Vestigial-Sideband (VSB) Modulation Technique 221 4.10 Comparison of AM, DSBSC, SSB and VSB 224 4.11 Applications of AM 224 Advance-Level Solved Examples 224 Chapter Outcomes 228 Important Equations 228 Key Terms with Definitions 229 Objective Type Questions with Answers 230 Multiple Choice Questions 232 Review Questions 234 Analytical Problems 235 Hands-on Projects: MATLAB Simulation Examples 238 5.1 Principles of Angle Modulation 249 5.2 Theory of FM—Basic Concepts 251 5.3 Spectrum Analysis of FM Wave 256 5.4 Narrowband and Wideband FM 261 5.5 Theory of Phase Modulation 267 5.6 Relationship between FM and PM 270 5.7 Advantages and Disadvantages of Angle Modulation 277 5.8 Comparison of AM, FM and PM 277 5.9 Applications of FM and PM 278 Advance-Level Solved Examples 278 Chapter Outcomes 282 Important Equations 282 Key Terms with Definitions 282 Objective Type Questions with Answers 284 Multiple Choice Questions 286 Review Questions 288 Analytical Problems 289 Hands-on Projects: MATLAB Simulation Examples 293 Introduction 302 6.1 AM Radio Transmitters 302 6.2 AM Radio Receivers 308 6.3 Noise Performance of AM (DSB-C) System 327 6.4 DSBSC Modulator and Demodulator 331 6.5 SSB Generation 338 6.6 SSB Receivers 346 6.7 Noise Performance of SSB Systems 350 6.8 FM Modulators and Transmitters 352 6.9 FM Receivers and Demodulators 361 6.10 Noise Performance of Angle-Modulation Systems 376 6.11 Communications Receivers 382 Advance-Level Solved Examples 385 Chapter Outcomes 390 Important Equations 391 Key Terms with Definitions 391 Objective Type Questions with Answers 392 Multiple Choice Questions 395 Review Questions 397 Analytical Problems 399 MATLAB Simulation Examples 403 Hands-on Projects: Hardware Implementations 411 Introduction 412 7.1 Digital Versus Analog Transmissions 412 7.2 Sampling Theorem 415 7.3 Classification of Pulse-Modulation Techniques 425 7.4 Pulse Amplitude Modulation (PAM) 426 7.5 Pulse Width Modulation (PWM) 431 7.6 Pulse Position Modulation (PPM) 434 7.7 Pulse-Code Modulation (PCM) 436 7.8 Quantization of Signals 441 7.9 Noise Performance of PCM Systems 451 7.10 Differential PCM (DPCM) 457 7.11 Adaptive Differential PCM (ADPCM) 462 7.12 Delta Modulation 464 7.13 Adaptive Delta Modulation 472 7.14 Continuous Variable Slope DM (CVSDM) 473 7.15 Comparison of PCM Techniques 474 7.16 Vocoders 475 Advance-Level Solved Examples 479 Chapter Outcomes 483 Important Equations 484