Ambient noise cancelation with a time-domain EMI measurement system using adaptive filtering

In this paper, an advanced digital signal processing technique for fast measurements of electromagnetic interference from electronic devices in the time-domain at open area test sites will be presented. Suppressing ambient noise by methods based on adaptive filtering algorithms, measurements of electromagnetic interference of a device under test can be performed at a test site polluted with electromagnetic ambient noise. Frequency domain adaptive filtering using the overlap-save method is applied. Measurement results of a real device under test are presented which show the successful cancellation of ambient noise at an urban test site in the frequency range 30 to 1000 MHz.