Wireless/RF is ubiquitous, so implement a pre-compliance regimen with off-the-shelf equipment. Every electronic product has to go through full electromagnetic compatibility (EMC) testing to get the much-coveted stamp of approval from the various regulatory bodies. This has traditionally been a costly undertaking with multiple trips to a distant testing facility, with … [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...]
Elephant in the Test Room #1 Continued – The Solid-State 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...]
Common Mode Emission. Can It Get Any Worse?
You betcha! Once upon a time I was in charge of EMC design for a large scale military digital telecommunications system. This system had to handle both red and black analog and digital data with the proviso that never the twain shall meet. In the lab where all the engineering tests were taking place everything went great until the cables were hung on the … [Read more...]
Mom! Dad! Do Open & Short Circuits Really Exist?
I debated whether I should introduce radiated pickup by the DM loop area next and then dismissed it so that I could continue with radiated emission from common mode (CM) currents. These tend to be very mysterious because they are typically caused by unbalanced differential mode (DM) currents. Often these are caused by a few extra grounds floating around somewhere in … [Read more...]
Radiated Emission from Green Electron Current
Well . . . I’m back. I hadn’t planned on being out of print so long and it will take a few paragraphs to bring everyone up to date.A number of you learned at the IEEE EMC Symposium in Pittsburgh that my family and I were taking our little travel trailer on an extended camping trip immediately after the symposium. There were several National Parks that we have wanted … [Read more...]
Unwanted Conductive and Radiative Emissions
The last post indicated that RF signal energy coupling from the emitter to the receptor can be by conduction or by radiation and that we would discuss that later. Well it’s later! The two coupling processes are very closely linked. Radiative coupling always starts out as a conductive signal and ends up as a conductive signal. In between and especially at … [Read more...]
Do I really need that signal?
We’ve been discussing signals from the perspective of their bandwidth relative to the bandwidth of the receptor and have not considered them from the EMC point of view. RF signal energy can get from the emitter to the receptor by conduction or by radiation. We’ll discuss that later. Regardless of the energy transfer process, using the FCC classification scheme we … [Read more...]
Impact of the Upcoming Medical RF Immunity Revision
As indicated last time, there are two key parties with a vested interest in the outcome of the upcoming Medical RF immunity revision:The test house manager who has to justify an upgrade to his test system to the people holding the purse strings.His customer, the company wishing to sell medical equipment compliant with the revised standard.I shall add a third … [Read more...]
Are they out to get us?
I didn’t realize when I addressed the smart meter RF situation that it was turning into such an uproar. Now, on top of the RADHAZ comments, people are expressing concern about protection of privacy. It seems that a lot of people have a difficult time believing in RF hazards because they can’t smell, feel, touch, taste, etc. the lower RF energy levels and, therefore, a hazard … [Read more...]
