The Office of Communications for the European Union has made EMC-related regulations for the London 2012 Olympics. The regulations, titled the "Wireless Telegraphy (Control of Interference from Apparatus) London Olympic Games Regulations 2012," seek to avoid electromagnetic interference with wireless communications during the events. Any item that may cause EMI must operate … [Read more...]
What is Differential and Common Mode Current?
Answering the title question will be a hot topic at the IEEE 2012 EMC Symposium in Pittsburgh. Hopefully many of you will have the chance to attend it this year. There are always some really great technical papers presented at this show – some more practical than others. If you’re there look me up. I’ll be spending some time at the Interference Technology booth, #817.The … [Read more...]
Power Grids Collapse in India; Are Smart Grids a Solution?
India was affected by a second power failure around 1 p.m. Tuesday, July 31, as three regional power grids collapsed, affecting 600 million people. A Powergrid Corporation spokesman told AFP the north, northeastern and eastern grids are down, but in the process of being fixed. Power sharing was reportedly to blame for the collapse. The northern grid drew on the eastern grid … [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...]
CEO and Founder of Elite Electronic Engineering, Inc., James C. Klouda, Passes Away
James Calvin Klouda, CEO and founder of Elite Electronic Engineering, Inc. Jim, 84, died July 10, 2012 with his family at his side. “Jim Klouda was an EMC testing pioneer, a brilliant engineer, a visionary, and a life-long entrepreneur, but most of all he loved people. He was a great man who always found the good in family, friends, employees and professional associates around … [Read more...]
Abracadabra the Broadband Signals Disappeared
Almost all EMC engineers these days are familiar with MIL-STD-461 and its various revisions because it has influenced the procedures in virtually all present day EMC standards. The original document and the A, B and C revisions all had requirements for measuring both broadband (BB) and narrowband (NB) emissions. When MIL-STD-461 was first released (July 31, 1967), the … [Read more...]
Another Look at Broadband Bandwidth Bandwidths
The last comment I made was regarding those perfect rectangular filters that we always describe with such reverence. But as I said, they don’t exist. Taking a receiver as an example, the filter amplitude versus frequency characteristics are measured by sweeping a narrowband signal through the passband frequency range of the circuit. Typically the passband width is … [Read more...]
Narrowband and Broadband Signals
As I indicated in the previous post, this discussion begins examining signal characteristics from an electromagnetic compatibility (EMC) perspective. But first, a few words to describe EMC. This is a relationship issue. We want all the equipment items to get along in peace and in harmony, but if one of them is a big source and the other is a wimpy receiver, they may not play … [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...]
