Category Archives: EMC Design

Some of my most popular articles

Hi All,

I thought you all might be interested in some of my most popular articles written for Interference Technology. Here are the top five:

The HF current probe: theory and application – http://www.interferencetechnology.com/the-hf-current-probe-theory-and-application/

Inexpensive radiated immunity pre-compliance testing – http://www.interferencetechnology.com/inexpensive-radiated-immunity-pre-compliance-testing/

Spread spectrum clock generation – theory and debate – http://www.interferencetechnology.com/spread-spectrum-clock-generation-theory-and-debate/

Troubleshooting radiated emissions using low-cost bench-top methods – http://www.interferencetechnology.com/troubleshooting-radiated-emissions-using-low-cost-bench-top-methods/

Harmonic comb generators are useful tools – http://www.interferencetechnology.com/harmonic-comb-generators-are-useful-tools/

Hope you enjoy them!

Measuring Resonance in Cables

Cables or other metal (antenna-like) structures often couple to sources of common-mode currents and end up radiating, causing product failures during compliance testing. During the troubleshooting process, it would be helpful to determine the resonance of these cables or structures to confirm they are the source of certain harmonic signals.

We could certainly measure the length of the cables or metal structures, but often, they are connected to other conductive assemblies, such as circuit boards or brackets. Because of these system inter-relationships, it’s not always easy to predict the resonances within a system, and so there’s always a little uncertainty as to where to start the troubleshooting process. These simple techniques may help quickly identify potential resonances within your system or product.

Continue reading…

Fig1 - Setup

Review: Right the First Time (Ritchey)

One of the most common questions I receive as an EMC consultant have to do with PC board design. And, no wonder. As clock and data frequencies increase towards 10 GHz, proper PC board design becomes an imperative for proper functioning of the system. The typical “rules of thumb” we used for low frequency boards no longer seem to apply.

RFT_coverweb

So, when I ran across Lee Ritchey’s self-published book, Right The First Time – A Practical Handbook on High Speed PCB and System Design (Volume 1), I was intrigued. Both this book and the follow-on volume 2 (Advanced Topics) are available on his web site. Volume 1 is now out of print, but available separately as a 295 page PDF file for just $25. However, both volumes may be purchased for the special price of $95 (the price of volume 2, alone) – a deal I highly recommend.  I’ll be reviewing volume 2 later. More…

Your EMC Questions Answered

Thanks for all the great questions presented following my recent EMC webinar, sponsored by Rohde & Schwarz and hosted by UBM TechOnline. If you missed the webinar, you may go here to download a copy of the slides and listen to the webinar “on-demand”. As I mentioned in the previous three postings, I’ve grouped them by topic and will be answering them all the best I can. Be advised that for many questions pertaining to EMC, the best answer is, “it depends”, so there may not be one answer for all cases. I’ll try to include my assumptions in the answers. The questions have been edited for clarity.

This posting will address general questions on EMC from my recent webinar that were not answered in previous installments. See more…

NEW! EMC Pocket Guide Published

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Randy Jost and I just released our new EMC Pocket Guide, which includes some basic product design guidelines and a whole bunch of reference data, charts and graphs that a product designer or EMC engineer might require on a day to day basis. The guide is available directly from the publisher, SciTech Publishing, for a special price right now of just $20 (regular price is $21.95). I’m not sure how long this special pricing will be in effect, so you may want to order a copy now.

DESCRIPTION

Every electric product designed and manufactured worldwide must meet electromagnetic compatibility (EMC) regulations, and yet, EMC compliance staff levels have been cut to the bone in companies large and small. If you are a working engineer or technician, the Electromagnetic Compatibility Pocket Guide is the first place to look while designing for EMC and your guide to thwarting electromagnetic interference.

KEY FEATURES
* Concise, constant-use guide addressing the most common reasons for compliance failure.
* Get needed answers quickly and move on to other design issues.
* Pocket-size, easy to carry and use, made of durable stock for continual service.
* Available for customization with your logo and marketing copy if you order in quantities.

TABLE OF CONTENTS

EMC Fundamentals
EMC Design
EMC Measurements
EMC Standards
Using Decibels
Frequency vs. Wavelength
Commonly Used Equations
Miscellaneous Information
Useful Software
References
* Books
* EMC Magazines
* EMC Organizations
* EMC Standards Organizations
* LinkedIn Groups
* Common Symbols
* EMC Acronyms

Questions on Radiated Emissions Pre-Compliance Testing

Following the recent webinar sponsored by Rohde & Schwarz, I received way too many questions to answer during the live presentation, so I’m following up gradually and posting my answers on The EMC Blog, now hosted by EDN.com.

I just posted my third article:

3. Questions on EMC pre-compliance testing for radiated emissions

I’ll be posting one more on the questions I received on general EMC topics some time in August.

In the meantime, I’ll be attending Doug Smith’s ESD/EMC three-day seminar next week and may write up a description with pictures. The week after that, I’ll be attending the annual International Symposium on EMC right here in Denver. I’ll be posting at least two articles on new products and other activities.

Your questions answered regarding cables and PC boards

Following the recent webinar sponsored by Rohde & Schwarz, I received way too many questions to answer during the live presentation, so I’m following up gradually and posting my answers on The EMC Blog, now hosted by EDN.com.

I’ve posted two articles so far:

1. Questions on cables for EMC mitigation

2. Questions on PC boards for EMC mitigation

I’ll be posting more soon on general EMC topics and pre-compliance testing for radiated emissions.