Many manufacturers design a product first, then attempt to “fix” the design later to meet the applicable safety standard. Prior knowledge of the applicable safety standard and its requirements for the product will help meet deadlines, keep design costs down, and result in a properly designed product.
Lessons Learned from the Design and Construction of an Open Area Test Site (OATS) and Sound Measurement Building
How do you construct a building without metallic components of any kind? When you are engineers charged with overseeing the design and construction of an Open Area Test Site (OATS) for your company, you find out very quickly how to build a structurally sound facility while still keeping the area free of reflective materials.
It’s been said that nobody grows up wanting to be an EMC engineer. Rather, it usually just happens. Maybe you had incriminating information on your resume, such as being a radio ham. “You’ve created interference, so you must know how to stop it, right?” Maybe you showed a knack for EMC troubleshooting, and suddenly you’re now the company expert - whether you want to be or not.
The first broadcasting station in Japan went on-air in 1925, a scant five years after the first radio station went live in the United States. A year later, Nippon Hōsō Kyōkai (NHK) was chartered by the Japanese government and is still the official public broadcast entity. The build-out of NHK’s network into the Pacific was extensive in the 1930s and during the early years of WWII and followed the expansion of Japan’s imperial armed forces across the Pacific.
This article describes some of the everyday issues that can arise in a working EMC test laboratory which may affect the quality of the measurements made and illustrates these with real-life examples that demonstrate the importance of robust pre-test verifications. The main focus is on emissions testing, as this is perhaps the area where most problems can occur without being detected. The article also looks at how using various types of reference source during pre-test verifications can help identify those problems and prevent invalid measurements being made.
When calibrated test equipment is found in an out-of-tolerance condition, there is additional risk to all products on which it was used. It is important to understand the magnitude of the potential risk because it can lead to dangerous consumer situations and additional business costs.
Sooner or later, anyone involved with EMI will be involved in troubleshooting an EMI problem, wherever it may surface. Most commonly, the problems will be uncovered during EMI testing, generally very late in the product design cycle, resulting in costly patches and schedule delays. It is best if preliminary EMI testing is done early in the design stage - EMI problems can be uncovered early enough that corrective action can be done in a timely fashion, ideally at the circuit board level. On the back end, EMI problems are often encountered in the field - perhaps because the environment is harsher than that expected by the regulatory agencies or because of an installation problem.