As an EMC consultant, it seems that lately I’ve run into many client projects where radiated immunity has cropped up as the major issue. One reason for this may be the trend in using digital and analog circuits that are powered by 3.3 volts, and lower, which decreases noise margins significantly. Sensitive analog circuitry is also greatly affected. The compliance testing for … [Read more...]
Training the Intern and Elephant in the Test Room #2 Continued
Read other posts in the "Elephant in the Test Room" series here.Elephant #2 - Disharmony in Harmonic LimitsThe Room: RF immunity testingThe Elephant: The curbing of the contribution made by harmonics to a calibrated test-field varies wildly from standard to standard, and within standardsThe Culprit: Harmonic limits that are seemingly not well thought through, and / or are open … [Read more...]
What’s in a Word?
I learned a new term the other day, and it actually seemed to catch a lot folks by surprise, myself included. I am very used to hearing and am very familiar with the term “electromagnetic environment” or EME. For the US DoD, the EME is defined as (from Joint Publication 1-02):“The resulting product of the power and time distribution, in various frequency ranges, of the … [Read more...]
The Linearization of EMC Amplifiers Continued & Introduction to Elephant in the Test Room #2
Read other posts in the "Elephant in the Test Room" series here.As promised in the last post, here is the start of the next elephant! Elephant #2 - Disharmony in Harmonic LimitsThe Room: RF immunity testingThe Elephant: The curbing of the contribution made by harmonics to a calibrated test-field varies wildly from standard to standard, and within standardsThe Culprit: Harmonic … [Read more...]
To EMP or Not to EMP… Is That the Question?
So what are our thoughts on the threat of an electromagnetic pulse event (God forbid) causing some sort of catastrophic damage to our telecommunications, power, and whatever other kind of electronic infrastructure that might be out there? I know, I know…it depends who you talk to! Being in the EMC business, I’d like to believe that I understand the fundamental issue (danger) … [Read more...]
Elephant in the Test Room #1 Continued – Linearization of EMC Amplifiers
Read other posts in the "Elephant in the Test Room" series here.Recap On this ThreadThe room: MIL-STD RF immunity testing – 1-18GHz 200v/mThe elephant: everyone in the room is aware that a significant fraction of the ‘calibrated’ 200v/m test field is actually created at the wrong test frequency.The culprit: notoriously high ‘start of band’ harmonics produced by all octave band … [Read more...]
They’re Everywhere, They’re Everywhere – Part II
In part one of this post, I noted that there are three primary EMC coupling problems that are associated with the green wire safety ground: 1. The green wire conducted noise current modulates the signal and shows up as a differential voltage change across the load.2. The green wire forms a pick-up loop and acts like a magnetic field antenna.3. The green wire loop acts as a … [Read more...]
They’re Everywhere, They’re Everywhere – Part I
Read Part II here.I just finished rearranging my office. It all started with buying a new MS Windows 8 computer (that’s a story all on its own) followed closely by the failure of my printer to feed paper. So I bought a new printer, which is about two times bigger than my old one, and it wouldn’t fit in the previous location. So I moved my little flat screen TV into the old … [Read more...]
Elephant in the Test Room #1 Continued – The Final Piece in the Conventional Approach
Read other posts in the "Elephant in the Test Room" series here.Recap On this ThreadThe room: MIL-STD RF immunity testing – 1-18GHz 200v/mThe elephant: everyone in the room is aware that a significant fraction of the ‘calibrated’ 200v/m test field is actually created at the wrong test frequency.The culprit: notoriously high ‘start of band’ harmonics produced by all octave band … [Read more...]
|∆N SASAC | > 4dB, and What’s Next?
Note: This article has been translated from Polish to English. It can be found in its original language in the 2014 Europe EMC Guide. Jan Sroka, Professor, Warsaw University of Technology, Warsaw, Poland ABSTRACT The term "site attenuation" is used in the theory of electromagnetic fields as extension of the term "attenuation," which is well known in circuit theory. The site … [Read more...]
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