Testing for EMC Compliance

MARK I. MONTROSE is an expert in the fields of regulatory compliance, electromagnetic compatibility (EMC) and product safety. He has performed extensive research in the areas of EMC theory and signal integrity, and has written numerous papers on the subjects. Mr. Montrose is also a Senior Member of the IEEE and a member of the Board of Directors of both the IEEE EMC and Product Safety Engineering Society, as well as an active participant in local, national, and international activities of both Societies. He has published two prior books related to EMC and printed circuit boards. EDWARD M. NAKAUCHI has over thirty years of experience in analog, power, and digital design and has spent the majority of the past twenty years working in the EMI/EMC/EMP and ESD areas for military aerospace companies as well as commercial audio, computer, and medical organizations. He has written numerous technical papers and magazine articles, and presented seminars on various EMI/EMP/ESD topics. He has also taught courses on EMI/EMC through the University of California Irvine Extension program. He is a NARTE certified EMC/ESD engineer and an IEEE Senior Member.

"…a very comprehensive book that should stand the test of time…I recommend book to design and test engineers…as it is likely to be referred to again and again." (IET.com) "The authors have developed a logical approach to understanding testing for EMC." (IEEE EMC Society Newsletter, Summer 2006)

• Preface xiiiAcknowledgments xvii1 Introduction 11.1 The Need to Comply 11.2 Definitions 31.3 Nature of Interference 51.4 Overview on Product Testing 61.4.1 Test Environment 61.4.2 Self-Compatibility 81.4.3 Validation of Measured Data 91.4.4 Problems during Emissions Testing 101.5 Time-Domain versus Frequency-Domain Analysis 121.6 EMC Testing Methodologies 141.6.1 Development Testing and Diagnostics 151.6.2 Compliance and Precompliance Testing 15References 162 Electric, Magnetic, and Static Fields 172.1 Relationship between Electric and Magnetic Fields 172.2 Methods of Noise Coupling 222.2.1 Common-Impedance Coupling 242.2.2 Electromagnetic Field Coupling 252.2.3 Conductive Coupling 272.2.4 Radiated Coupling–Magnetic Field 272.2.5 Radiated Coupling–Electric Field 282.2.6 Radiated and Conducted Coupling Combined 312.3 Common-Mode Currents versus Differential-Mode Currents 322.3.1 Differential-Mode Currents 322.3.2 Common-Mode Currents 332.3.3 Example on Difference between Differential- and Common-Mode Currents 332.3.4 Radiation due to Differential-Mode Currents 362.3.5 Common-Mode Radiation 382.3.6 Conversion between Differential- and Common-Mode Energy 392.4 Static Fields 402.4.1 Electrostatic Discharge Waveforms 412.4.2 Triboelectric Series 412.4.3 Failure Modes From a Static Event 43References 463 Instrumentation 473.1 Time-Domain Analyzer (Oscilloscope) 473.1.1 Oscilloscope Probes 523.2 Frequency-Domain Analyzers 533.2.1 Spectrum Analyzers 573.2.2 Receivers 643.3 Precompliance versus Compliance Analyzers 663.4 Correlation Analyzer 683.4.1 Characteristics of Cancellation System 703.4.2 Coherence Factor 71References 754 Test Facilities 774.1 Open-Area Test Sites 784.1.1 Requirements for an OATS 784.1.2 Test Configuration—System, Power, and Cable Interconnects 854.1.3 Operating Conditions 874.1.4 Measurement Precautions 954.1.5 Alternate Test Sites 954.2 Chambers 964.2.1 Anechoic Chamber 974.2.2 Screen/Shield Rooms 1044.2.3 Reverberation Chamber 1074.3 Cells 1094.3.1 TEM Cell 1094.3.2 GTEM Cell 110References 1125 Probes, Antennas, and Support Equipment 1135.1 Need for Probes, Antennas, and Support Equipment 1135.2 Voltage Probes 1155.3 Current Probes 1165.3.1 Specifying a Current Probe 1185.3.2 Limitations When Using Current Probes 1225.4 LISN/AMN (AC Mains) 1245.5 CDNs (Data and Signal Lines) 1285.6 Absorbing Clamp 1305.6.1 Test Setup and Measurement Procedure 1325.7 Bulk Current Injection—Probe and Insertion Clamp 1345.7.1 Choosing a BCI Probe 1355.8 Basic Probe Types—Near Field and Closed Field 1375.9 Sniffer Probes 1405.9.1 Near-Field Probes 1425.9.2 Commercial Probes 1435.10 Differential-Mode Probes 1435.11 Home-Made Probes 1465.12 Alternate Troubleshooting Devices 1475.13 Far-Field Antennas 1505.13.1 Common Antennas Used for EMC Testing 153References 1566 Conducted Testing 1576.1 Overview of Conducted Currents 1576.1.1 Common- and Differential-Mode Currents on Wires and Cables 1596.1.2 Coupling Paths for Conducted Emissions 1616.1.3 Conducted Emissions Test Requirements 1636.2 Performing Conducted Current Tests 1636.2.1 Engineering Investigation in Laboratory or Engineer’s Office 1636.2.2 Test Environment 1646.3 Conducted Emissions Testing (AC Power Mains) 1646.3.1 Potential Problems during Conducted Emission Testing 1666.3.2 In Situ Testing of Systems and Installations 1676.4 Immunity/Susceptibility Tests 1686.4.1 Electrical Fast Transient and Burst Testing 1696.4.2 Surges 1746.4.3 Conducted RF Current Immunity 1816.4.3.1 Coupling Methods 1816.4.3.2 Typical Conducted Immunity Test Setup and Equipment 1846.4.3.3 Performing Typical Conducted Immunity Test 1896.4.3.4 Diagnosis and Fixes 1916.4.4 AC Mains Supply Dips, Dropouts, and Interruptions 1926.4.4.1 AC Mains Supply Sags/Brownouts 1956.4.4.2 Swell Testing 1966.4.4.3 Three-Phase Equipment—Compliance Testing 1986.4.4.4 Diagnosis and Fixes 1986.4.5 Power Line Harmonics 1996.4.5.1 How Harmonics Are Created and Related Concerns 2006.4.5.2 Diagnosis and Fixes 2116.4.6 Voltage Fluctuation and Flicker 2116.4.6.1 Description of Short-Term Flicker 2126.4.6.2 Instrumentation 213References 2157 Radiated Testing 2177.1 Performing Radiated Tests 2187.1.1 Engineering Investigation in Laboratory or Engineer’s Office 2207.1.2 Precompliance Testing 2207.1.3 Performing Precompliance Analysis 2237.1.4 Formal EMC Qualification Tests 2247.1.5 Instrumentation Error 2257.1.6 In Situ Testing of Systems and Installations 2277.2 Immunity/Susceptibility Tests 2287.2.1 Radiated Immunity 2297.2.1.1 Modulation 2317.2.1.2 Harmonic Issues 2337.2.1.3 Monitoring of Immunity Field Level 2347.2.2 Electrostatic Discharge 2347.2.2.1 General Information 2357.2.2.2 ESD Waveforms 2357.2.2.3 Triboelectric Series 2367.2.2.4 Typical Test Setup 2377.2.2.5 EUT Performance Criteria 2417.2.2.6 Diagnosis and Fixes 2417.2.2.7 Concerns Related to Analyzing ESD Events 2427.2.2.8 Alternative ESD Test Simulator 2437.2.2.9 Other Uses for ESD Simulator 2447.2.2.10 Sensing ESD Events within One’s Environment 2457.2.3 Power Frequency Magnetic Field Disturbance 2457.2.3.1 General Conditions 2467.2.3.2 EUT Performance Criteria 2467.2.3.3 Typical Test Setup 2477.2.3.4 Waveform Verification 2497.2.3.5 Performing the Test 249References 2508 General Approaches to Troubleshooting 2518.1 General System Testing and Troubleshooting 2528.1.1 Emission Testing 2538.1.2 Immunity Testing 2558.1.3 In Situ Testing 2568.2 Potential Problems During Testing and Troubleshooting 2598.3 Testing and Troubleshooting Concerns 2638.3.1 Systematic Approach for Emission Testing and Troubleshooting 2648.3.2 Systematic Approach for Immunity Testing and Troubleshooting 2668.3.3 Systematic Approach to Detecting and Locating Problems 2678.3.4 Minimum Requirements for Performing EMC Tests 2718.4 Repeatability of System Testing 2728.5 Unexpected Problems after Production Has Begun 2758.6 Creative Approaches to Troubleshooting (Case Studies) 276References 2779 On-Site Troubleshooting Techniques 2799.1 Quick Fixes and Solutions 2809.1.1 Conducted Solutions 2819.1.2 Radiated Solutions 2879.1.3 Crosstalk Solutions 2919.2 Simplified Troubleshooting Techniques 2929.2.1 The “Plain Wave and Standing Wave” Technique 2939.2.2 The “Disabling-the-System” Technique 2939.2.3 The “Cable Disconnection” Technique 2949.2.4 The “Sticky Finger” Debugging Tool 2959.2.5 The “Sharpen-Your-Pencil” Tool 2969.2.6 The “Coolant Spray” Tool 2979.2.7 The “Piece-of-Wire” Approach 2989.2.8 The “Radio Control Race Car Diagnostic Sensor 2989.2.9 The “Tin Can Wireless Antenna” for Signals above 1 GHz 3009.3 Testing and Troubleshooting Using Probes 3019.3.1 Using Probes for Immunity Testing and Troubleshooting 3019.3.2 Differential Measurement of RF Currents on Cables and Interconnects 3059.3.3 Switching Power Supply Effects on Common-Mode Conducted Noise 3089.3.4 Discrete Component Diagnostic Tool 3109.3.5 Tweezers Probe 3119.3.6 Miniature High-Discrimination Probe 3129.3.7 Using Current Probe as Substitute for Radiated Emission Testing 3139.3.8 Enclosure Resonances and Shielding Effectiveness 3159.4 Alternate Troubleshooting Techniques 3169.4.1 Using Oscilloscope to Debug Signal Integrity Waveforms and Radiated Emissions 3169.4.2 Using Inexpensive Receivers for Emissions Testing 3199.4.3 Using Amateur Radio Transmitter for Immunity Testing 3219.4.4 Radiated Problem Masked as Conducted Emission Problem 3229.4.5 Determining Whether Conducted Emission Noise is Differential Mode or Common Mode 3239.4.6 Another Use of EFT/B Generator 3249.4.7 Signal Integrity Observations 3259.5 System-Level Troubleshooting 3269.5.1 Switching Power Supplies—Measuring Magnetic Field Coupling 3269.5.2 Potential Problems When Using Ferrite Cores—Increase in Radiated Emissions 3289.5.3 Measuring Shielding Effectiveness of Materials and Enclosures 3309.5.4 Measuring Effects of High-Frequency Noise Currents in Equipment 3339.5.5 Measuring Noise Voltage across Seams in Enclosures 3369.6 Ambient Cancellation or Suppression 3399.7 Printed Circuit Board Diagnostic Scanners 341References 345Appendix A Building Probes 347Appendix B Test Procedures 375Glossary 435Bibliography 447Index 453About the Authors 459