louis martin
cns news & features
Santa Rosa, California--
On January 1, 1996 consumer electronic products sold in Europe will have to meet a new standard. They will have to be certified as fully operational in the presence of other electronic devices emitting electromagnetic energy.
"The difference between Europe and the U.S.," said Clay Bilby, Electromagnetic Compatibility Product Manager at Hewlett-Packard in Santa Rosa, "is quite extreme. In the U.S. there are no susceptibility or ems requirements." As January 1 approaches, said Bilby, there is going to "virtual panic" among manufacturers of equipment that does not meet the new standard.
Susceptibility to radiated electromagnetic fields is measured by generating a field and observing how a product reacts to it. The difficulty of performing tests depends on the size of the product. Said Bilby, "If the product is small, then you can test the product within a metal box. If you have large, complex products, then it's more difficult to test."
The problem is this. The testing must be performed within a metal enclosure because the signals used for testing cannot be radiated out into the environment. The high energy fields would disrupt communications and affect many electronic products.
For large electronic products it takes a special chamber in which to perform tests. Large metal rooms with special, energy-absorbing tiles and cones on the walls are required. Said Bilby, "They can cost anywhere from a half a million dollars up to a couple of million dollars."
For many companies, this is a large investment. As a result, there are companies that now specialize in this type of testing.
As part of the test scenario, Hewlett-Packard has announced a new product to test the electromagnetic immunity of consumer products. The 84300A can test both "conducted" and "radiated" susceptibility. "Conducted susceptibility," said Bilby, "is where we inject a signal onto a power cord or a cable connecting up to an instrument, and we see how that instrument responds when this signal is injected onto it."
For radiated susceptibility, a field is created using an antenna. "It's kind of like being near a transmitter for a radio station." A product is placed into the field to see how it reacts.
The Hewlett-Packard 84300A can be purchased in various configurations. For one that tests conducted susceptibility only, the price is $75,000. For one that tests only radiation susceptibility, the price ranges from $150,000 to $200,000 depending on options. To test for both types of susceptibility, the price is about $210,000.
Other companies make equipment that could be used to test for susceptibility, and the U.S. military has been doing it for years, according to Bilby. "Obviously they (the military) don't want a detonator to go off on an explosive because a pilot turns on his radio."
The U.S. does have emissions standards for commercial electronic products.
(10/11/95)