A brief introduction... Keith Armstrong, Cherry Clough Consultants, Brockton, Stafford, UK This new publication (August 2008) EMC for Functional Safety published by the Institute of Engineering and Technology (IET) replaces the IEE’s 2000 edition. The Guide comprehensively describes practical and cost-effective procedures that can be utilized by both management and … [Read more...]
Uncertainty of Measurements
Measurement uncertainty is not limited to EMC. Robert D. Goldblum, Publisher Emeritus, ITEM Media ANSI C63.23/D11, is a draft standard for Electromagnetic Compatibility – Calculations (Computations) and Treatment of Measurement of Uncertainty being prepared by the American National Standards Institute (ANSI).1 When published, this standard is likely to be adopted by the … [Read more...]
M2M and 3G Wireless Integration Challenges
Author Bruce E. Touzel, Cisco Systems, Inc. The Opportunity More and more, 3G wireless modems are finding their way into places other than your typical mobile phones and laptops for internet connection. A term called M2M (machine-to-machine) is defining the new 3G communications link between machines for telemetry and other industrial & commercial purposes such … [Read more...]
Meeting Military Requirements for EMC and Transient Voltage Spike Suppression
The basics of EMI and transient compliance for military systems using SMPSs are covered. Dr. Glenn Skutt, VPT, Inc., Blacksburg, Virginia, USA THE EMI AND VOLTAGE TRANSIENT CHALLENGE Military and aerospace engineers face several challenges with respect to electromagnetic interference (EMI) and transient voltage compliance. The standards developed by the various military … [Read more...]
Inrush Current in DC-DC Converters
Some applications may require limiting the inrush spike into the input capacitors. Steve Butler and Jeremy Ferrell, VPT, Inc., Blacksburg, Virginia, USA BACKGROUND Inrush current is the spike of current drawn by a power supply when it is turned on. A typical power system is shown in Figure 1. The input EMI filter will include some capacitance connected across the input … [Read more...]
A Discussion on the FCC SAR Test Guidance Documents for Laptops and Handsets with Multiple Transmitters
The FCC will address exactly what TCBs can review for SAR and simultaneous transmitters in future updates to the TCB exclusion list. David A. Case, Cisco Richfield, Ohio, USA For those involved with product approval for Federal Communications Commission (FCC) certification, the use of the Telecommunication Certified Body (TCB) for approval helps speed the process for product … [Read more...]
Sometimes an EMI Test Failure is not an EMI Test Failure – Lessons Learned in the Real World of Shielded Enclosure Testing
EMI testing in an unusual environment takes more time than testing in a lab environment. Ed Kirchner, Harris Corporation, Melbourne, Floria, USA Jeff Prosser, Rubicom Systems, Melbourne, Floria, USA Grant Lohsen, Georgia Tech Research Institute, Atlanta, Georgia, USA INTRODUCTION A Harris Corporation test team recently performed a shielding effectiveness test on a welded … [Read more...]
Evaluation of the Printed Circuit Board Power Distribution Network Design and Its Effect on EMI
Authors Norm Smith (Teradata Corp.), Jun Fan (UMR), John Andresakis (Oak-Mitsui Technologies), Mark Harvey (Sanmina-SCI), Jim Knighten (Teradata Corp.) Abstract Embedding capacitive layers inside the Printed Circuit Board (PCB) have demonstrated the ability to reduce the number of Surface Mount Technology (SMT) chip decoupling capacitors on the PWB surface as well as … [Read more...]
