When I opened my e-mail this morning, I found about 50 bounce messages in my inbox. Apparently, a spammer  is using my e-mail address m.rowe@tmworld.com to send spam. The company spam filter has caught over 700 bounces in the last six hours. I set up some rules to automatically delete incoming messages with subject lines such as "Message delivery Failed," that get through the spam filter, but a few others still get through.

If you receive spam that appears to be from me, please be assured that it's not.

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While browsing through newsgroup sci.engr.electrical.compliance last night, I came upon a posting for an online engineering calculator. At www.calculatoredge.com, you'll find calculators for numerous engineering fields such as electrical, electronics, physics, mechanical engineering, and chemical engineering. In the electrical, electronics, and physics sections, the site provides calculators and circuit diagrams for filters (Butterworth, Chebyshev, and others), bridges, antennas, attenuators, and many others. The next time you need a quick calculation, give this site a try.

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Yesterday, I attended Tech Tour, a traveling road show for EMC engineers. Presenters from Silent, ETS-Lindgren, and Rohde & Schwarz gave talks on topics such as shielding, antennas, and spectrum analyzers, respectively.

Prior to the first presetnation, I spoke with two EMC engineers. One asked the other, "With all the equipment and automation tools available today, do you think the witchcraft is gone?"

"Witchcraft isn't gone," replied the other engineer. "Even with specialized tools, you still have to know how to set them up and use them correctly."

What's your take on solving EMC problems? Is it still mysterious or is it more cookbook now?

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I'm working on an article with an engineer who modified a thermal chamber to cut RF emissions when testing RF SOCs. He needed to isolate the SOC under test from the test equipment and test the device over a wide temperature range.

I'm sure that many of you have come up with clever test setups for performing EMI/RFI testing. I've seen some who use chicken wire to form a shielding cage and others who have built their won makeshift screen rooms. Clearly, these ad hoc test setups won't work for compliance tests, but they can provide some degree of confidence that you've minimized EMI emission or immunity.

Have you come up with any ad hoc EMI/RFI/EMC test setups? I've like to discuss them with you. E-mail me at m.rowe@tmworld.com.

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Six months ago, I bought a laptop PC. Because I didn't want to use Windows Vista, I bought a used Dell through eBay. Since then, Microsoft announced that it will end sales of Windows XP on June 30, 2008. Because the laptop didn’t come with a Windows XP disk, I’m tempted to buy another copy of the operating system just in case I need to reload Windows.

PC-based test systems often have far longer lives than home or office computers. Many of you are still using Windows 2000, Windows 98, and even DOS. Because Windows Vista ...Read More

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I'm reading a book about jitter and noise when I ran across the word "impendance."

In the text, impendance is used in characterizing the transfer function of an RC network with regard to crosstalk, beginning with an equation. The book reads:

     V=Z_vC_m(dV_d/dt)

     Where Z_v is the impendence of the impacted or victim line and dV_d/dt is the time derivative of the driving voltage.

I immediately though that "impendence" should be "impedance." But, I Googled "impendence" and found things like...

 "Teseq Inc., a developer and provider of instrumentation and test systems for EMC emission and im...Read More

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A CNN story about electronic gadgets infecting PCs pointed to computers used for testing as the source of several viruses. "Electronic gadgets latest sources of computer viruses" reports the computers used to test digital photo frames and iPods have passed on viruses to these devices during final product testing. The devices then pass the viruses on to home computers through USB ports. According to the story, one person's antivirus software found four viruses--one of which could steal passwords--from a photo frame, .

If you have responsibility for any kind of production test, you owe it to your customers to check those computers for viruses. Of course, if your company uses overseas contract manufacturers, you don't always have tight enough control to verify virus-free products. You should spot check your products for viruses.

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I'm sitting here writing an article about A/D converters when I heard this great line on the radio. The line is:

Work is not the same as before
More software hands in the hardware store

The words come from "Oh Abraham" by John Gorka. Gorka often comes up
with clever lyrics like these.

Do you often feel that software is taking over? Should it?

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A reader e-mailed with a question about inrush current in USB 2.0 devices. Can you help? Post a comment below.

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I'm reading "USB 2.0: Compliance and beyond", which uses Agilent Application Note 1400 - "USB 2.0 Compliance Testing with Agilent Infiniium" as a reference.

This application note says "The USB 2.0 specification outlines a total inrush surge current limit of 50 μC."  The USB spec itself does not mention microcoulombs, instead specifying a load of no more than 10 μF in parallel with 44 Ω.&nbs...Read More

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I moved the TV from my father's house into my living room. The TV isn't one of these flat panel uints. It's a Philips 27-in. CRT, but its new and large compared to my 22-year-old 19-in. Samsung. It has all kinds of I/O jacks: component video input, S-video input, composite video input (2 sets), composite video and audio outputs, and an RF input. OK, it's not the latest, but it's got far more jacks than the old TV.

I spent yesterday morning connecting the TV to a cable box, DVD/VHS unit, and to my stereo. My goal was to integrate the DVD/VHS and cable units into my stereo cabinet with the TV on top. I knew it had enough space to fit the two additional units.

The cable box connects to the TV over the RF cable and the DVD/VHS connects to the TV through an S-video cable. I tried using the component video inputs but the picture as out of sync. The TV's audio output go...Read More

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This month's print cover story, Protection at full power, is about Littelfuse. It was the toughest story I ever had to write. It's not because of the Littlefuse people, though. They were great and they had cool stories to tell about how they test their products.

It's because of what happened after I left.

While waiting for my flight at O'Hare, I learned that I had lost my father. I spent the entire flight just staring out the window. Since then, I've been clearing things from his house. Dad had an old chest of drawers that was once in my room that he used as his electrical storage cabinet (see photo).
...Read More

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I'm about to be discharged from the hospital after three long days. Despite all the measuring the doctors have subjected upon me, they can't explain what happened over the weekend that brought me to the emergency room. I had some kind of attack (twice) that was quite painful, but both times the severe pain dissipated in about two hours. All the measurements of the last three days have turned up nothing and I feel fine. I might even be back in the office tomorrow. (I wonder if my editors will cut me some slack on my Friday deadline.) Well, at least I have my laptop and a solid wireless connection here in my room. The only snag is that I haven't been able to log into the company VPN to check my work e-mail. My personal e-mail works fine through the Web access.

What sort of measurements has the hospital inflicted on me? Of course, there's temperature, blood pressure, oxygen...Read More

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