Making Conducted and Radiated Emissions Measurements
Electromagnetic interference (EMI) compliance testing can be a costly bottleneck in the product development process. Full EMI compliance measurements require the use of a receiver that meets CISPR 16-1-1 requirements, a qualified open test site or semi-anechoic chamber, and an antenna tower and turntable to maximize EUT signals. Great effort is taken to obtain the best accuracy and repeatability. These facilities can be quite expensive. To help ensure successful EMI compliance testing, pre-compliance testing has been added to the development cycle. Pre-compliance measurements are intended to give an approximation of the EMI performance of the EUT but at a fraction of the cost of full compliance testing. In pre-compliance testing, the electromagnetic compatibility (EMC) performance is evaluated from early design through production units. Typical components used in pre-compliance measurement systems include a signal analyzer with bandwidths and detectors that meet regulatory requirements, EMI/EMC measurement software, a line impedance stabilization network (LISN), transient limiter and antennas. To isolate problems after they have been identified, close field probes are used.
Order this application note and receive detailed information on the basics of radiated and conducted emissions measurements, how to configure a pre-compliance measurement system and perform measurements, and other important factors related to EMI.