The Chicago Chapter of IEEE EMC Society , Invites you to our November 19, 2026 meeting.  

The topic of understanding modern EMI Measurement Equipment should be of interest to all EMC practitioners. 

Abstract: Traditionally, EMI Measurements are performed by spectrum analyzers or EMI receivers. Using the FFT-based measurement systems for EMI testing can reduce test time, improve the repeatability of EMI tests. While MIL461F defines the settings of dwell and sweep time for spectrum analyzers and EMI receivers, MIL461F defines the first-time parameters and requirements for the FFT-based measurement systems.

During the presentation the technological and mathematical background FFT-based measurement according to CISPR 16-1-1/ANSI C63.2 and MIL461 is explained. The requirements of CISPR 16-1-1/ANSI C63.2 and MIL461G regarding the implementation as well as the equivalence to a traditional EMI receiver ensure traceability and the same test results. The difference between an FFT-analyzer, a Real-time spectrum analyzer and the FFT-based measurement system are explained. Some pitfalls of using scopes with FFT-mode or noncompliant real-time spectrum analyzers for EMI testing are explained. Table 2 of MIL461G points out different parameters regarding the dwell time for stepped scan and FFT-based measurement system. During practical demonstration of the measurement of fluctuating signals, it is explained why a longer dwell time for FFT-based measurements according to MIL461G is required. Also, the advantages regarding the reproducibility and reduction of test time is shown. In addition to traditional scanning FFT-based measuring instruments also offers new methods to visualize and analyzer signals. During the presentation also the usage of spectrogram, time-domain analysis and complaint Real-time spectrum analyzer are shown. Applications like the detection of cycles of emissions as well as the identification of sources using correlation methods are shown. In addition, the changes given in MIL461H regarding EMI testing is presented.

DLS Electronic Systems, Inc.

Wheeling, IL 60090