Emi protection for_communication_systems

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  • 1. EMI Protection forCommunication Systems

2. DISCLAIMER OF WARRANTYThe technical descriptions, procedures, and computer programs in this book havebeen developed with the greatest of care and they have been useful to the author in abroad range of applications; however, they are provided as is, without warranty ofany kind. Artech House, Inc. and the author and editors of the book titled EMI Pro-tection for Communication Systems make no warranties, expressed or implied, thatthe equations, programs, and procedures in this book or its associated software arefree of error, or are consistent with any particular standard of merchantability, orwill meet your requirements for any particular application. They should not berelied upon for solving a problem whose incorrect solution could result in injury to aperson or loss of property. Any use of the programs or procedures in such a manneris at the users own risk. The editors, author, and publisher disclaim all liability fordirect, incidental, or consequent damages resulting from use of the programs or pro-cedures in this book or the associated software.For a listing of recent related Artech House titlesturn to the back of this book. 3. EMI Protection forCommunication SystemsKresimir Malaricartechhouse.com 4. Library of Congress Cataloging-in-Publication DataA catalog record for this book is available from the U.S. Library of Congress.British Library Cataloguing in Publication DataA catalogue record for this book is available from the British Library.ISBN-13: 978-1-59693-313-2Cover design by Greg Lamb 2010 ARTECH HOUSE685 Canton StreetNorwood, MA 02062All rights reserved. Printed and bound in the United States of America. No part of this bookmay be reproduced or utilized in any form or by any means, electronic or mechanical, includ-ing photocopying, recording, or by any information storage and retrieval system, withoutpermission in writing from the publisher. All terms mentioned in this book that are known to be trademarks or service marks havebeen appropriately capitalized. Artech House cannot attest to the accuracy of this informa-tion. Use of a term in this book should not be regarded as affecting the validity of any trade-mark or service mark.10 9 8 7 6 5 4 3 2 1Disclaimer:This eBook does not include the ancillary media that waspackaged with the original printed version of the book. 5. ContentsPrefacexiiiCHAPTER 1Communications Systems11.1 Components of Communications Systems11.2 Transmitter Systems 21.2.1 Transmitter 31.2.2 Randomization 41.2.3 Encryption51.2.4 Encoder 51.2.5 Interleaving91.2.6 Modulation 101.2.7 Mixer (Upconverter)101.2.8 Filter 111.3 Receiver Systems 111.3.1 Filter 111.3.2 Mixer (Downconverter)121.3.3 Demodulator121.3.4 Deinterleaver121.3.5 Decoder131.3.6 Decryptor151.3.7 Derandomizer 151.3.8 Demultiplexer161.3.9 Received Power 161.4 User Interface 181.4.1 Graphical User Interface (GUI) 181.4.2 Voice User Interface (VOI) 191.5 Antenna Systems191.5.1 Duplexer 191.5.2 Antenna201.6 Power Supplies 221.6.1 Power Supply Types 231.6.2 Power Amplifier23 v 6. viContents 1.7 Considerations for Voice Versus Data23 1.7.1 Text23 1.7.2 Images24 1.7.3 Voice 24 1.7.4 Video 24 Selected Bibliography 24CHAPTER 2 Electromagnetic Spectrum Used for Communications27 2.1 Electromagnetic Spectrum27 2.1.1 Extra Low Frequency (ELF) 28 2.1.2 Super Low Frequency (SLF) 28 2.1.3 Ultra Low Frequencies (ULF) 29 2.1.4 Very Low Frequency (VLF)29 2.1.5 Low Frequency (LF)29 2.1.6 Medium Frequency (MF) 29 2.1.7 High Frequency (HF) 29 2.1.8 Very High Frequency (VHF) 29 2.1.9 Ultra High Frequency (UHF)29 2.1.10 Super High Frequency (SHF) 30 2.1.11 Extra High Frequency (EHF) 30 2.1.12 Infrared (IR)30 2.1.13 Visible30 2.2 Spectrum Division 30 Selected Bibliography 33CHAPTER 3 Electromagnetic Properties of Communications Systems35 3.1 Fundamental Communications System Electromagnetics35 3.1.1 Smith Chart 39 3.1.2 Snells Law of Reflection and Refraction42 3.2 Wave Generation and Propagation in Free Space 44 3.2.1 Maxwells Equations 44 3.2.2 Wave Propagation46 3.2.3 Wave Polarization 47 3.2.4 Fresnel Knife-Edge Diffraction48 3.2.5 Path Loss Prediction51 3.3 Wave Generation and Propagation in the Terrestrial Atmosphere 53 3.3.1 Absorption and Scattering 53 3.3.2 Wave Propagation in the Atmosphere54 Selected Bibliography 55CHAPTER 4 Electromagnetic Interference57 4.1 Electromagnetic Interference with Wave Propagation and Reception57 4.1.1 Additive White Gaussian Noise (AWGN)57 7. Contentsvii 4.1.2 Thermal Noise 58 4.1.3 Shot Noise58 4.1.4 Flicker (1/f ) Noise58 4.1.5 Burst Noise 59 4.1.6 Noise Spectral Density59 4.1.7 Effective Input Noise Temperature 59 4.2 Natural Sources of Electromagnetic Interference 59 4.2.1 Lightning and Electrostatic Discharge 59 4.2.2 Multipath Effects Caused by Surface Feature Diffraction and Attenuation 64 4.2.3 Attenuation by Atmospheric Water65 4.2.4 Attenuation by Atmospheric Pollutants 67 4.2.5 Sunspot Activity68 4.3 Manmade Sources of Electromagnetic Interference 69 4.3.1 Commercial Radio and Telephone Communications 69 4.3.2 Military Radio and Telephone Communications 74 4.3.3 Commercial Radar Systems74 4.3.4 Industrial Sources75 4.3.5 Intentional Interference76 Selected Bibliography 77CHAPTER 5 Filter Interference Control 79 5.1 Filters79 5.1.1 Lowpass Filter 80 5.1.2 Highpass Filter80 5.1.3 Bandpass Filter81 5.1.4 Bandstop Filter83 5.1.5 Resonator83 5.2 Analog Filters 85 5.2.1 Butterworth Filter 85 5.2.2 Chebyshev Filters86 5.2.3 Bessel Filters 87 5.2.4 Elliptic Filters 88 5.2.5 Passive Filters88 5.2.6 Active Filters 91 5.3 Digital Filters91 5.3.1 FIR Filters93 5.3.2 IIR Filters94 5.4 Microwave Filters97 5.4.1 Lumped-Element Filters 97 5.4.2 Waveguide Cavity Filters 98 5.4.3 Dielectric Resonator100 Selected Bibliography 101 8. viii Contents CHAPTER 6 Modulation Techniques 103 6.1 Signal Processing and Detection 103 6.2 Modulation and Demodulation 105 6.2.1 Analog Modulations105 6.2.2 Digital Modulation112 6.3 Control of System Drift 120 Selected Bibliography 120CHAPTER 7 Electromagnetic Field Coupling to Wire123 7.1 Field-to-Wire Coupling123 7.1.1 Skin Effect 123 7.1.2 Unshielded Twisted Pair (UTP) 125 7.1.3 Ferrite Filter126 7.2 Electric Field Coupling to Wires128 7.3 Magnetic Field Coupling to Wires131 7.4 Cable Shielding 132 7.4.1 Tri-Axial Cable 133 7.4.2 Cable Termination 133 7.4.3 Shielded Twisted Pair Cables134 Selected Bibliography 136CHAPTER 8 Electromagnetic Field-to-Aperture Coupling137 8.1 Field-to-Aperture Coupling137 8.1.1 Shielding Effectiveness (SE)138 8.1.2 Multiple Apertures138 8.1.3 Waveguides Below Cutoff 140 8.2 Reflection and Transmission 141 8.2.1 Electric Field145 8.2.2 Magnetic Field146 8.3 Equipment Shielding 147 8.3.1 Gasketing 147 8.3.2 PCB Protection148 8.3.3 Magnetic Shield 149 Selected Bibliography 151CHAPTER 9 Electrical Grounding and Bonding153 9.1 Grounding for Safety154 9.1.1 Shock Control 154 9.1.2 Fault Protection155 9.2 Grounding for Voltage Reference Control 156 9.2.1 Floating Ground 156 9.2.2 Single Point Ground 157 9. Contents ix 9.2.3 Multipoint Ground158 9.2.4 Equipotential Plane158 9.3 Bonding for Current Control159 9.3.1 Bonding Classes160 9.3.2 Strap Bond for Class R 160 9.3.3 Resistance Requirements162 9.4 Types of Electrical Bonds162 9.4.1 Welding and Brazing163 9.4.2 Bolting163 9.4.3 Conductive Adhesive164 9.5 Galvanic (Dissimilar Metal) Corrosion Control164 Selected Bibliography166CHAPTER 10 Emissions and SusceptibilityRadiated and Conducted167 10.1 Control of Emissions and SusceptibilityRadiated and Conducted167 10.1.1 Sources of Electromagnetic Interference 167 10.1.2 Test Requirements for Emission and Susceptibility 171 10.1.3 Standard Organizations173 10.2 Commercial Requirements 177 10.3 Military Requirements 178 10.3.1 Specific Conducted Emissions Requirements Mil-Std 461E178 10.3.2 Specific Conducted Susceptibility Requirements Mil-Std 461E 179 10.3.3 Radiated Emissions Requirements Mil-Std 461E181 10.3.4 Radiated Susceptibility Requirements Mil-Std 461E 182 Selected Bibliography182 CHAPTER 11 Measurement Facilities 185 11.1 Full Anechoic and Semianechoic Chambers 185 11.1.1 Absorbers 187 11.1.2 Ferrite Tiles 189 11.2 Open Area Test Site (OATS)191 11.3 Reverberation Chamber 193 11.4 TEM Cell195 11.4.1 Characteristic Impedance196 11.4.2 Higher-Order Modes197 11.4.3 TEM Cell Construction 198 11.4.4 Parameter Measurements200 11.5 GTEM Cell 201 11.5.1 GTEM Cell Characteristics 203 11.5.2 GTEM Cell Construction203 11.5.3 GTEM Cell Parameter Measurement 204 11.5.4 Current Distribution at Septum211 Selected Bibliography212 10. x Contents CHAPTER 12Typical Test Equipment21512.1LISNLine Impedance Stabilization Network 21512.2Coupling Capacitor21612.3Coupling Transformer21712.4Parallel Plate for Susceptibility Test21712.5Coupling Clamps and Probes218 12.5.1 Capacitive Coupling Clamp 219 12.5.2 Current Probe 22012.6Injection Clamps and Probes 221 12.6.1 Current Injection Probe 221 12.6.2 EM Clamp221 12.6.3 Electrostatic Discharge (ESD) Generator 22312.7EMI Receiver22412.8Spectrum Analyzer 22512.9Oscilloscopes 225 Selected Bibliography225CHAPTER 13Control of Measurement Uncertainty22713.1 Evaluation of Standard Uncertainty 22713.1.1 Type A Evaluation of Standard Uncertainty22713.1.2 Type B Evaluation of Standard Uncertainty22813.2 Distributions22813.2.1 Normal (Gaussian) Distribution 22913.2.2 Rectangular Distribution 22913.2.3 U-Shaped Distribution23013.2.4 Combined Standard Uncertainty23013.2.5 Expanded Uncertainty 23113.3 Sources of Error 23113.3.1 Stability23113.3.2 Environment23113.3.3 Calibration Data 23113.3.4 Resolution 23213.3.5 Device Positioning 23213.3.6 RF Mismatch Error23213.4 Definitions232Selected Bibliography 232Appendix A Communication Frequency Allocations235A.1 Frequency Allocation in the United States 235A.2 International Frequency Allocation245 11. Contents xi Appendix B List of EMC Standards Regarding Emission and Susceptibility 255 B.1 Cenelec255 B