Electromagnetic Compatibility Engineering

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Electromagnetic Compatibility Engineering

Introduction

Electromagnetic Compatibility Engineering

    Electromagnetic Compatibility Engineering is a completely revised, expanded, and updated version of Henry Ott's popular book Noise Reduction Techniques in Electronic Systems. It reflects the most recent developments in the field of electromagnetic compatibility (EMC) and noise reduction¿and their practical applications to the design of analog and digital circuits in computer, home entertainment, medical, telecom, industrial process control, and automotive equipment, as well as military and aerospace systems.

While maintaining and updating the core information—such as cabling, grounding, filtering, shielding, digital circuit grounding and layout, and ESD—that made the previous book such a wide success, this new book includes additional coverage of:

• Equipment/systems grounding
• Switching power supplies and variable-speed motor drives
• Digital circuit power distribution and decoupling
• PCB layout and stack-up
• Mixed-signal PCB layout
• RF and transient immunity
• Power line disturbances
• Precompliance EMC measurements
• New appendices on dipole antennae, the theory of partial inductance, and the ten most common EMC problems

The concepts presented are applicable to analog and digital circuits operating from below audio frequencies to those in the GHz range. Throughout the book, an emphasis is placed on cost-effective EMC designs, with the amount and complexity of mathematics kept to the strictest minimum.

Modeling and Analysis of Dynamic Systems

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TABLE OF CONTENTS

Preface xxiii

Part 1 EMC Theory 1

1 Electromagnetic Compatibility 3

1.1 Introduction 3

1.2 Noise and Interference 3

1.3 Designing for Electromagnetic Compatibility 4

1.4 Engineering Documentation and EMC 6

1.5 United States’ EMC Regulations 6

1.6 Canadian EMC Requirements 19

1.7 European Union’s EMC Requirements 20

1.8 International Harmonization 26

1.9 Military Standards 27

1.10 Avionics 28

1.11 The Regulatory Process 30

1.12 Typical Noise Path 30

1.14 Miscellaneous Noise Sources 33

1.15 Use of Network Theory 36

Summary 38

Problems 39

References 41

Further Reading 42

2 Cabling 44

2.1 Capacitive Coupling 45

2.2 Effect of Shield on Capacitive Coupling 48

2.3 Inductive Coupling 52

2.4 Mutual Inductance Calculations 54

2.5 Effect of Shield on Magnetic Coupling 56

2.6 Shielding to Prevent Magnetic Radiation 64

2.7 Shielding a Receptor Against Magnetic Fields 67

2.8 Common Impedance Shield Coupling 69

2.9 Experimental Data 70

2.10 Example of Selective Shielding 74

2.11 Shield Transfer Impedance 75

2.12 Coaxial Cable Versus Twisted Pair 75

2.13 Braided Shields 79

2.14 Spiral Shields 81

2.15 Shield Terminations 84

2.16 Ribbon Cables 94

2.17 Electrically Long Cables 96

Summary 96

Problems 98

References 103

Further Reading 104

3 Grounding 106

3.1 AC Power Distribution and Safety Grounds 107

3.2 Signal Grounds 120

3.3 Equipment/System Grounding 132

3.4 Ground Loops 142

3.5 Low-Frequency Analysis of Common-Mode Choke 147

3.6 High-Frequency Analysis of Common-Mode Choke 152

3.7 Single Ground Reference for a Circuit 154

Summary 155

Problems 156

References 157

Further Reading 157

4 Balancing and Filtering 158

4.1 Balancing 158

4.2 Filtering 174

4.3 Power Supply Decoupling 178

4.4 Driving Capacitive Loads 186

4.5 System Bandwidth 188

4.6 Modulation and Coding 190

Summary 190

Problems 191

References 192

Further Reading 193

5 Passive Components 194

5.1 Capacitors 194

5.2 Inductors 203

5.3 Transformers 204

5.4 Resistors 206

5.5 Conductors 208

5.6 Transmission Lines 215

5.7 Ferrites 225

Summary 233

Problems 234

References 237

Further Reading 237

6 Shielding 238

6.1 Near Fields and Far Fields 238

6.2 Characteristic and Wave Impedances 241

6.3 Shielding Effectiveness 243

6.4 Absorption Loss 245

6.5 Reflection Loss 249

6.6 Composite Absorption and Reflection Loss 257

6.7 Summary of Shielding Equations 260

6.8 Shielding with Magnetic Materials 260

6.9 Experimental Data 265

6.10 Apertures 267

6.11 Waveguide Below Cutoff 280

6.12 Conductive Gaskets 282

6.13 The ‘‘IDEAL’’ Shield 287

6.14 Conductive Windows 288

6.16 Internal Shields 293

6.17 Cavity Resonance 295

6.18 Grounding of Shields 296

Summary 296

Problems 297

References 299

Further Reading 300

7 Contact Protection 302

7.1 Glow Discharges 302

7.2 Metal-Vapor or Arc Discharges 303

7.3 AC Versus DC Circuits 305

7.4 Contact Material 306

7.5 Contact Rating 306

7.6 Loads with High Inrush Currents 307

7.7 Inductive Loads 308

7.8 Contact Protection Fundamentals 310

7.9 Transient Suppression for Inductive Loads 314

7.10 Contact Protection Networks for Inductive Loads 318

7.11 Inductive Loads Controlled by a Transistor Switch 322

7.12 Resistive Load Contact Protection 323

7.13 Contact Protection Selection Guide 323

7.14 Examples 324

Summary 325

Problems 326

References 327

Further Reading 327

8 Intrinsic Noise Sources 328

8.1 Thermal Noise 328

8.2 Characteristics of Thermal Noise 332

8.3 Equivalent Noise Bandwidth 334

8.4 Shot Noise 337

8.5 Contact Noise 338

8.6 Popcorn Noise 339

8.7 Addition of Noise Voltages 340

8.8 Measuring Random Noise 341

Summary 342

Problems 343

References 345

Further Reading 345

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