Most engineers employ good design practices to minimize the potential for EMI problems. Still, to identify and address any potential EMI issues before formal compliance testing, it is considered best practice to perform in-house pre-compliance measurements during the design and prototyping stages. This reduces the risk that the product will fail final compliance tests at the test house.
Also, in the event of a failure during formal testing, the ability to test in one's own lab gives the time to methodically isolate problem areas and test different corrections.

After taking pre-compliance measurements, the results must be recorded and documented for future use. Creating a report similar to the certification lab report may help one discover potential issues and gain confidence before the formal certification tests. Whereas making notes on a general-purpose spectrum analyzer may be challenging, PC-based test and analysis software simplifies the report generation process. A “report wizard” in EMCVu simplifies report generation by allowing one to specify the information to include in the report, and allowing one to merge multiple test results. Reports may be output in several formats, including PDF, MHT, XLSX and several image formats.

Once issues have been found in pre-compliance tests, what’s next? Troubleshooting the issues and locating the sources of RF emissions. The real-time DPX® technology in Tektronix spectrum analyzers can help discover the most difficult, hard-to-find problems. It enables one to see RF characteristics that are practically invisible to a conventional spectrum analyzer.

EMI compliance testing for automotive components and subsystems is an important part of the design process, and it usually occurs quite late. Pre-compliance testing can take help mitigate stress on projects and by taking the right steps, one can have higher confidence that your design will pass at the test house. New, relatively low-cost instruments and software are available to help minimize testing expense and achieve schedule commitments while getting the products EMI certified.