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The concepts of: controlling signal integrity; improving signal-to-noise ratios; minimizing development of common-mode potentials; controlling - confining unintended common-mode fields and effects into defined regions for efficient functional partitioning and systems-product integration for all high frequency – high speed digital designs; (including analogue-digital separations) may all be categorized as subsets of the first axiom of Electromagnetic Compatibility: THE SYSTEM-PRODUCT DESIGN MUST BE FUNCTIONALLY COMPATIBLE WITHIN ITSELF! This intra-system product compatibility is inclusive of signal and product performance to functional definitions, requirements and specifications. The derivation of a common-mode architectural design from the system-product electrical architecture is essential to efficiently implement functional (electromagnetic) compatibility within a systems-product.


Session 1.1 - Introduction to: common-mode effects; field coupling transfers; common-mode architecture; and, Electromagnetic Compatibility:

  • Blocked and Lumped Equivalent Model, Simplified, Descriptions
  • Coupling Interrelationships to Chassis Structure
  • Interface Connections as Antenna Equivalents
  • Overview of Conductive-Case Shielding Containment
  • Initial Susceptibility “Intrusions” Presented by ESD, representing common-mode effects
  • Interface Role as “Exit and Entry Currents” in Susceptibility – Immunity Performance
  • Overview of common-mode and EMC Architectural Considerations.

Session 1.2 – Logic Devices and Circuit Boards: Causal Relationships of Common-mode Fields and Potentials from circuit devices

  • Logic Drivers and Cross-Conduction Currents
  • Spectral Propagation Characteristics of Various Waveforms
  • Spread Spectrum Approaches to Distribute Spectral Occupancy
  • Common-mode Structures Within Circuit Boards
  • Significance of Propagation Through an Imperfect Plane – Inductive Formations
  • Peak Currents and Repetitive Impulse Surges
  • Coupling of Common-mode Potentials to Heat Sinks and Heat Sink Arrays
  • Storage Capacitors: Layout Locations, Methods, Rationale and Resonances
  • “Array” Effect of Multiple Circuit Devices
  • Interface Wires and Cables as Antenna Structures

Session 1.3 – Field Transfers To Structures from Circuit Boards: Common-mode Current Circulations and Coupled Effects

  • Concept of Distributed Common-mode Transmission Lines
  • Relationship and Modes of Field Transfers to Chassis Planes (Mechanical Structures)
  • Chassis Planes as Common-mode Image Returns in Distributed Line and Surface Patch Modes
  • Spectral Profile Alterations Derived from Imposition of Chassis Planes
  • Common-mode Field Potential Displacements and Transfer Impedances to Chassis Structures
  • Multi-Mode Propagation Arrays
  • Equivalent “Antenna Radial Propagation” of Common-mode Currents in Interface Wires and Cables
  • Beneficial Use of “Ground Nulls” to Establish Controlled Reflections Within Distributed Common-mode Field Displacements
  • Susceptibility Effects with “Ground Null” Implementations
  • Intervals of “Ground Nulls”
  • Concepts of Partitioning Through “Moats” and “Isolation Zones”

Session 1.4 – Circuit Board Layout Considerations: Delineated for Signal Quality, Power Quality, Common-mode Loss Reductions and Architectural Controls

  • Concept Review of Transmission Lines in Signal and Power Distributions
  • Flux Linkage and Inductance Cancellation
  • Dichotomous “Breaks” in Transmission Lines, and Occurrences of “Break-equivalents” in Circuit Boards
  • Descriptions of Return Images in Relationship to Flux Linkage
  • Reviews of Transmission Lines:
    • Micro-Stripline
    • Stripline
    • Embedded Micro-Stripline
    • Asymmetrical Stripline
    • Edge-Coupled Differential Line
    • Broadside Coupled Differential Line
  • Transmission Line Impedance Characteristics of Line Configurations Noted Above
  • Flux Linkage Patterns and Rationale
  • Power Plane Configurations and Impedances with Signal Imaging
  • Circuit Board “Stack-up” Considerations for Power and Signal Distributions
  • Power Planes and Edge Impedance Terminations
  • Undercut Power Planes – Concept, Rationale and Implementation
  • Multiple Dielectric Separations
  • Skin Effect and Skin Depths
  • “3-W” and “10-W” Trace Width Rules for Flux Boundaries of Traces
  • Signal and Power Imaging for Various Board Stack-ups Transmission Line Image Return Skew with Layer-Jumping Through Vias
  • Skew Route Patch for above
  • Factors for Consideration of Imaging on Voltage Planes
  • Signal Impedance Matching
  • Series and Parallel Signal Trace Terminations
  • Circuit Board Functional (Common-mode and EMC Architectural) “Partitioning”
  • Blind and Buried Via Applications
  • Faraday “Fences” Used for Partitioning
  • “Picket Fences” Within Circuit Boards for Board-Level Isolation Partitions
  • 3-Dimensional Partitions
  • Analogue-Digital Partitioning
  • Common-mode Inductor Techniques and Valuations
  • Susceptibility / Immunity Partitioning in Circuit Boards
  • Derivative of Circuit Board Topologies and EMC Architecture from Systems Electrical Architecture – Preliminary Approach.

Session 2.1 – Paralleled Common-mode Loss and Field Transfer Relationships of “Stacked” Circuit Boards

  • Common-mode Developments and Coupling With Interconnected Circuit Boards
  • Common-mode and EMC Issues Using Interconnected Circuit Boards With Interface Cable Configurations
  • Common-mode Displacements of Paralleled and Interconnected Circuit Boards With Interface Cables
  • Electromagnetic Field Transfers and Displacement Interactions Of Paralleled Circuit Boards
  • Field Interactions Between Paralleled Boards and Chassis Structures
  • Ground “Null” Applications to Paralleled Circuit Boards to Develop Signal / Noise Partitions
  • Topology and Partitioning of Paralleled Circuit Boards
  • Backbone Implementation for Partitioning Between Paralleled Circuit Boards.

Session 2.2 – Perpendicular Bus-Structure Circuit Boards with Motherboards: Common-mode Architectural Descriptions

  • Common-mode Essentials of Perpendicularly – Connected Circuit Boards
  • Common-mode Architectural Considerations With Perpendicular Circuit Boards
  • Common-mode Field Distributed Transfer Interactions
  • Field Displacements to Chassis Planes - Structures
  • Common-mode Transfers In Architectural Paths to Interface Cables
  • Field Transfer Interactions to Interface Cables With Multiple Cards
  • EMC Implications of Ancillary Connections to Perpendicular Circuit Boards
  • Ground Null Applications to Motherboards and Perpendicular Interface Circuit Boards
  • Topological Layout Implications of Common-mode Fields

Session 2.3 – Backplane and Midplane Products Integrated with Individual and Multiple Card Cages: Common-mode Architecture to Minimize Intra-System Coupling

  • Backplanes Viewed Initially With A Single Interconnected Systems Board
  • “Lumped Effects” of Common-mode Considerations
  • Card Cage Impositions With Backplanes With Interconnected Systems Board
  • Field and Current Transfers to Card Cages from Interconnected Systems Boards with (and to) Backplanes
  • Backplane Architecture to Systems Boards
  • Preliminary Common-mode Architectural and EMC Implications of Interface Connections
  • Susceptibility / Immunity Implications of Interface Common-Mode Architecture
  • Conceptual Approach of Midplane Integration
  • Common-mode Aspect Ratios of System Boards
  • Interface Cable Connections to Backplanes and Systems Boards
  • Interconnections of Multiple Systems Boards
  • Approximation of Antenna Structures Referenced to Chassis (Card Cage) Planes
  • Common-mode References of Backplanes With Systems Boards
  • Common-mode Current Circulation Closure
  • Special Situation: Chassis Connection References for DC Chassis-Isolated Backplanes
  • Reference Technique With Chassis Stripes and Via Patterns
  • Establishment of “Null Zones” in Backplanes
  • Null Zones and Regional Partitions
  • Inter-layer Backplane Referencing Method With Connection Detail
  • Backplane Layering Construction, Stack-up Considerations
  • Distributed DC Power Sub-System Integration through Backplane to Systems Boards
  • System Board Topology for Distributed DC Power Subsystem
  • Interconnected Systems-Card Edge Reference Application
  • Card Guide Connection Null Approach
  • Null Partition References of Interconnected Systems Boards
  • Derivation of Common-mode EMC Architecture from Systems Electrical Architecture
  • Null Partition References – Card Cage and Backplane Integration
  • Termination of Null Partitions to Backplane
  • Mid-Planes - Partition Integration
  • Mid-Plane Partitions and Stack-up Concepts
  • Mid-Plane Common-Mode Architectural Derivation

Session 2.4 – EMC Implications of Systems Interconnections

  • Initial Implications Related to Systems Interconnections
  • EMC Issues Affecting Radiated Field Susceptibility and Emissions
  • Interrelationships of Currents Between Systems Units
  • Spatial EMC Excitations Among Systems Unit Members
  • Rack-Mount EMC Integration of Multiple Card Cage Products
  • Multiple Card Cage Products – Independently and Remotely Mounted
  • Common-mode EMC Excitations Imposed to Mechanical Mounting Structures
  • Field Transfers (Interactions) Between Multiple Card Cage System Products
  • Lumped Representations of Multiple Card Cage Products
  • Rack-mount Integration of Multiple Card Cage Products
  • EMC Mitigation Methods for Rack Mount Products
  • Distributed Common-mode Attenuation Technique Through Interface Cables
  • Implications of Primary (Utility) Power Interconnections
  • Interconnections to Facility Power Distributions
  • Historical Implications of Facility Common-mode Events
  • Voltage and Current Ground Shifts From Facility Power That Impact Systems’ Architecture
  • Alternate Architectural Systems Structure to Mitigate Facility Common-mode Events
  • Concept of Software Coding and Physical Interface Transport Communication Layers
  • Essential EMC Characteristics of Telecommunication Physical Transport Layers
    • Multi-wire Cables
    • Twin-axial Cables
    • Tri-axial Cables

Session 2.5 - Immunity / Susceptibility Considerations

  • Common-mode Entry and Exit Currents (to or from systems-products)
  • Null Redistributions of Common-Mode Exit Currents
  • Implications of Redistributions to Shielded Cables
  • Common-Mode to Differential-Mode Conversions
  • Common-Mode Current Circulating in the Shield of the Cable Wire Pairs
  • EMC Reference Interactions with Chassis-Case Structures
  • Overview of Case-Structure Apertures and Field Redistribution
  • Transfer Mechanisms of Susceptibility Response
  • Effects of Product Immersion into Radiated Field Excitation Structures
  • Concepts of Bandwidth Limiting (Filtering / Conditioning)
  • Single-ended Signals, Conducted Series Common-mode Intrusions and Superimposition
  • Common-mode and Differential-mode Approaches
  • Concepts of Demodulation and Detection of RF Carrier Processes
  • Electrostatic Discharge (ESD) Processes and Impacts
  • Fast Transient (EFT) Coupled Impacts
  • Radiated Field Influences.

Session 3.1 – Product Shielding: Application of Conceptual Theory

  • Properties of Electromagnetic Waves
  • Concepts of Electromagnetic Wave Impedance Mismatches With Shields
  • Transmission Line Analogies of Shielding Processes
  • Electromagnetic Wave Impedances
    • Near Field
    • Transition Region
    • Far Field
  • Electromagnetic Wave Impingement – Shield Performance Mechanisms
  • Reflection Losses From Shield Surfaces
  • Initial Reflection Shielding Function of a Boundary
  • Skin Effect Boundaries
  • Inter-boundary Effects
    • Thick Shields
    • Thin Shields
    • Surface Boundary Shields
  • Shielding Effectiveness Functions of a Continuous Shield Boundary
    • Reflection Losses
    • Absorption Losses
  • Compilations of Shielding Effectiveness Parameters

Session 3.2 – Perimeter Case and Chassis Shielding: Gaps, Seams, Slots, Perforations and Waveguides Operating Below Cutoff

  • Factors Limiting Shield Performance
  • Coincidence of Apertures to Circuits and Circuit Boards
  • Applications of Seams and Gaps as Shield Apertures
  • Induction Flux Equivalence in Shield Gap Formations
  • Aperture-Arrayed Shield Structures – Ventilation (Cooling) Applications
  • Waveguides in Cutoff – Individual Apertures
  • Waveguides in Cutoff – Aperture Arrays
  • Ventilation Path – Plenum Shield Indirect Impingement Concepts
  • Cavity Resonance in Enclosure Plenums
  • Waveguides in Cutoff – Performance Examples
  • Perforated Metals and Screen Shield Performance Examples
  • Honeycomb Shield Arrays
  • Rectangular and Circular Waveguides
  • Induction Field External Coupling to Cables from Apertures

Session 3.3 - Shielded Modules Carried on Circuit Board As Partitions

  • Device-level Heat Sinks Utilized as Shields
  • Completing Shields of Device-level Heat Sinks
  • Regional Shield Partitions with Lumped Coupling Approximations
  • Regional Shield Partition – Topology Routing Plans
  • V-Plane Partitioning in Regional Boundaries
  • Inner-Board Shielding Partitions with “Picket Fence” Via Patterned Arrays
  • Partition Integration with “Shields” for Externally-Removable Circuit Modules
  • Partitions Developed Within Boundaries of Removable Circuit Modules
  • Cavity Resonance Effects and “Q-Factor”

Session 3.4 - Cable Shielding Applications

  • Purpose of Cable Shielding
    • Tri-axial Cable Shields
    • Twin-axial Cable Shields
    • Twisted Pairs
    • Unshielded Twisted Pairs
  • Cable Shield Construction Details
  • Cable Shields as Boundary Partitions
  • Common-mode Cable “Image Return” Functions of Chassis, Structures, and Earth
  • Importance of Connector Characteristics
  • Shield Categories of Multi-Conductor Shielded Cables
  • Twisted and Twisted-Shielded Pairs Within Multi-Conductor Cables
  • Significance of Shield Termination Impedance

Session 3.5 – Personnel Electrostatic Discharge: History; Delineated ESD Wave-Shape Continuum for Multiple Conditions as Found in Nature; Comparisons of ESD Continuum to Requirements of IEC Standards

  • Delineated Descriptions of ESD Waveforms and Implied Spectra Found “In Nature”
    • Human “Finger-Tip” ESD Events
    • ESD Event Waveforms From Personnel Through Metallic Intervening Objects
    • ESD Event Waveforms from Personnel Through “Mobile Furnishings”
  • ESD Mechanisms of Propagation to Systems-Products Under Varied Installation Conditions
Session 4.0 – Specific Design Reviews: Examination of Specific Products in Comparison to the Examples Provided in the Course.
  • Additional instruction may be provided as an extension of the course by performing specific design reviews on systems-product designs in conjunction with the responsible development teams. This option tends to improve the significance and retention of the course instruction by applying the examples directly to “real-hardware”. The design reviews typically utilize comparative examples extracted from the course material in explanatory application to the results of the systems-product design investigations and reviews. The product examples selected for design review are intended to be unique and proprietary to the client contracting for this course. Depending on the number of products examples selected and the detail of the review, additional time may be required for the course schedule.
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