Monthly Archives: September 2012

Make Your Own EMC Troubleshooting Kit (Download)

I recently posted a new technical paper to my EMC web site: “Making Your Own EMC Troubleshooting Kit”. This downloadable pdf file includes a summary of the six-part series of articles on the Test & Measurement World web site in The EMC Blog. I describe the complete list of contents, plus some advice on selecting a low-cost spectrum analyzer.

Here’s the download…

Review: The ARRL RFI Book (3rd Edition)

In my never-ending quest to search out useful reference books on EMC, I recently ran into the 3rd edition of “The ARRL EMC Book” (ISBN 9780872590915). First published in 1999, the new 3rd edition was released in 2010. For those unfamiliar with the ARRL (Amateur Radio Relay League), this is the national organization representing amateur radio operators (“hams”) in the U.S. Most hams are members of the league, which also publishes a range of useful operating, design and general radio reference books. Because hams are allowed to operate their two-way radios at up to 1.5kW, on occasion, this may be the cause of local interference to poorly-designed or poorly-shielded consumer products. Thus, several years ago it was decided to publish a reference book on RFI (radio frequency interference). In this article, I’ll describe the most important content and why you might want to buy it. More…

Using MathCad to Simulate a Square Wave

There are a number of engineering tools that work well for simulating EMC scenarios. One of these is MathCad, a tool that’s been around for a number of years. The neat thing about MathCad is that you can define a set of equations in free-form layout and plot out the analysis in several engineering-type graphs, including logarithmic and polar. These plots are easily copied and may be pasted into documents or technical papers.

As an example, I’ve calculated the harmonic content of a square wave given user-defined fundamental frequency, rise times, pulse widths and duty cycles. It’s very instructive to run through several scenarios prior to building hardware. By changing any of the user-defined parameters, you can quickly judge the outcome. More…

Using A Tracking Generator

Many spectrum analyzers include tracking generators, but some new engineers my not completely understand what the purpose is and how they can help with certain measurements. In a nutshell, tracking generators are variable, or swept, RF generators that “track” with the spectrum analyzer sweep frequency. Some tracking generators have a limited frequency sweep as compared with their mating spectrum analyzer, so you need to know any frequency limitations in advance. In this article, I’ll use the new Rigol DSA815TG and the built-in tracking generator to measure a 150 MHz bandpass filter and a 10 dB attenuator. More…

EMC Archive at T&M World Now On-Line

Martin Rowe, Sr. Editor of Test & Measurement World, recently collected over 80 EMC-related blog posts and articles published in the last several years and has placed them all into a single location in the T&M World “Vault”. Look for “EMC EMI RFI ESD“.

Check them out!

The RF Explorer 3G Released Today

RF Explorer is a handheld digital spectrum analyzer covering 15 MHz to 2.7 GHz. It is based on a highly integrated frequency synthesizer and double balanced mixer which offers high performance, compact size, low consumption and low cost. I’ve been beta-testing the unit for some time now and can confirm it works well as an affordable general-purpose analyzer.

Being battery-operated (chargeable via USB), it makes a great EMC troubleshooting tool. Probably, the major disadvantage is the limited user interface, being just seven push buttons, but there is available freeware PC and Mac remote client software to run and display waveforms. The display is also limited in resolution, but for the price, it’s tough to complain too much!

To read a review of the older model, which is very similar, click here…

The new RF Explorer is available now through SeeedStudio for $269.

Where do you turn for help?

While most larger companies may be able to afford just one EMC engineer (or a small handful) to cover all products under development, many smaller companies can’t afford one at all and must rely on their existing designers to deal with compliance issues (many times at the end of the product development process!). So where does the lone EMC engineer or inexperienced product designer turn to for help in answering EMC questions?

Here are a few answers.