ATI Grounding and Shielding for EMC Course



This three-day course is designed for technicians, operators, and engineers who need an understanding of all facets of grounding and shielding at the circuit, PCB, box or equipment level, cable-interconnected boxes (subsystem), system and building, facilities or vehicle levels. The course offers a discussion of the qualitative techniques for EMI control through grounding and shielding at all levels. It provides for selection of EMI suppression methods via math modeling and graphics of grounding and shielding parameters. Our instructor will use computer software to provide real world examples and case histories. The computer software simulates and demonstrates various concepts and helps bridge the gap between theory and the real world. The computer software will be made available to the attendees. One of the computer programs is used to design interconnecting equipments. This program demonstrates the impact of various grounding schemes and different "fixes" that are applied. Another computer program is used to design a shielded enclosure. The program considers the box material; seams and gaskets; cooling and viewing apertures; and various "fixes" that may be used for aperture protection. .

There are also hardware demonstrations of the effect of various compromises and resulting "fixes" on the shielding effectiveness of an enclosure. The compromises that are demonstrated are seam leakage, and a conductor penetrating the enclosure. The hardware demonstrations also include incorporating various "fixes" and illustrating their impact.

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    1. Introduction. A Discussion Of EMI Scenarios, Definition Of Terms, Time To Frequency Conversion, Fourier Series Transfers, Narrowband-Vs-Broadband, System Sensitivities, Reciprocity With Emissions And EMI Prediction..  
    2. Potential EMI Threats (Ambient). An Overview Of Typical EMI Levels. A Discussion Of Power Line Disturbances And A Discussion Of Transients, Including ESD, Lightning And EMP.  
    3. Victim Sensitivities And Behavior. A Discussion Of Victim Sensitivities Including Amplifier Rejection, Out-Of-Band Response, Audio Rectification, Logic Family Susceptibilities And Interference- To-Noise Versus Signal-To-Noise Ratios.  
    4. Safety Earthing/Grounding Versus Noise Coupling. An Overview Of Grounding Myths, Hard Facts And Conflicts. A Discussion Of Electrical Shock Avoidance (UL, IEC Requirements), Lightning Protection And Lightning Rods And Earthing.  
    5. Ground Common Impedance Coupling (GCM). A Discussion Of Practical Solutions, From PCB To Room Level. An Overview Of Impedance Of Conductors (Round, Flat, Planes), Class Examples, GCM Reduction On Single Layer Cards, Impedance Reduction, DC Bus Decoupling And Multilayer Boards.  
    6. Field Coupling Into Ground Loops (FCM). A Discussion Of The Field Conversion Coefficient, Techniques For FCM Reduction, Class Examples Of Cable Coupling Versus Box Coupling And Why Cable Coupling Is Usually The Largest Factor In EMI.  
    7. Ground Loop Coupling (GLC). A Discussion Of Common-Mode To Differential-Mode Conversion, The Effect Of Parasitic Capacitances And Examples.  
    8. GLC Reduction Methods. A Discussion Of Floating And Single-Point Grounds, Balanced Drivers And Receivers, RF Blocking Chokes, Signal Transformers And Baluns, Ferrites, Feed-Through Capacitors And Opto-Electronics.  
    9. Field-To-Cable Differential Coupling (DMC). An Overview Of Field-To-Pair Coupling Coefficient, Twisting And Class Examples.  
    10. Cable Shields, Balanced Pairs And Coax. A Discussion Of Cable Shields And Compromising Practices, Shielding Effectiveness, Field Coupling, Interactions Of Ground Loops With Balanced Pair Shields, Comprehensive Grounding Rules For Cable Shields, Flat Cables And Connector And Pigtail Contributions To Shielding Effectiveness.  
    11. Application Examples. Examples Of Composite (CM & DM) Coupling, AM Broadcast Field Jamming Of An Analog Link, Manual Calculations And Computer Predictions Using CAD 5220.  
    12. Radiated Emissions, Prediction And Reduction. A Discussion Of Prime Radiation Sources - Chips And Traces, Tables And Nomograms For Easy Predictions, Application Exercises (RF Emissions From 10 Mhz Clock), And Cable Contributions - Reciprocity Of Emission Versus Susceptibility.  
    13. Cable-To-Cable Coupling (Xtalk). A Discussion Of The Basic Model, Capacitive And Magnetic Couplings, A Class Example And How To Reduce Xtalk.  
    14. Power Line Coupling. An Overview Of CM And DM Coupling Through Power Lines, Transformer Parasitic Coupling, Faraday-Shielded Transformers, Switch-Mode Power Supply Conducted Noise Versus FCC/VDE Limits, A Prediction Example - Noise Suppression, A Summary Of Power Line Disturbance Remedies, Complete Room Treatment (Power And Ground), Surge Protectors, And A Practical Example - Fixing An Industrial Process Computer.  
    15. Understanding Shielding Theory. An Overview Of Near-Field E And H, Far-Field, How A Metal Barrier Performs And Reflection And Absorption.  
    16. Shielding Effectiveness (SE) Of Barriers. A Discussion Of Performance Of Typical Metals, Low-Frequency Magnetic Shields, Conductive Coatings/Metallized Plastics And Aircraft Composites (CFC).  
    17. Box Shielding - Leakage Reduction. A Discussion Of A General Model For Box SE, Calculation Of Apertures SE, Combination Of Multiple Leakages, SE Of Screen Meshes, Conductive Glass, Waveguide Effects - Honeycombs, Component Penetrations (Fuses, Switches, Etc.), And EMI Gaskets.  
    18. How To Design The Right Box From The Start. An Overview Of Establishing Box SE Requirements, Box Skin Performance, Aperture/Seam Leakage - Quick Prediction, And A Class Exercise - Shielding A Video Terminal Against 10 V/M Up To 10 Ghz.

Speaker and Presenter Information

Dr. William G. Duff (Bill) received a BEE degree from George Washington University in 1959, a MSEE degree from Syracuse University in 1969, and a DScEE degree from Clayton University in 1977. Bill is an independent consultant specializing in EMI/EMC. He worked for SENTEL and Atlantic Research and taught courses on electromagnetic interference (EMI) and electromagnetic compatibility (EMC). He is internationally recognized as a leader in the development of engineering technology for achieving EMC in communication and electronic systems. He has more than 40 years of experience in EMI/EMC analysis, design, test and problem solving for a wide variety of communication and electronic systems. He has extensive experience in assessing EMI at the circuit, equipment and/or the system level and applying EMI mitigation techniques to "fix" problems. Bill has written more than 40 technical papers and four books on EMC. He is a NARTE Certified EMC Engineer. Bill has been very active in the IEEE EMC Society. He served on the Board of Directors, is currently Chairman of the Fellow Evaluation Committee and is an Associate Editor for the Newsletter. He is a past president of the IEEE EMC Society and a past Director of the Electromagnetics and Radiation Division of IEEE.

Relevant Government Agencies

Air Force, Army, Intelligence Agencies, DOD & Military, Dept of Energy, NASA, Other Federal Agencies, CIA, Census Bureau


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    When
    Tue-Thu, Feb 1-3, 2011, 8:30am - 4:30pm



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