MIL STD 46IF CS101 testing and power frequency cancelation

The MIL-STD-461F CS101 test is one of the essential conducted immunity tests for military equipment. The CS101 test includes some challenges in application. One of them is the necessity for the measurement of injected CS101 ripples under the power frequency of the EUT (Equipment Under Test). Especially for low frequencies which are very close to the power frequency, the measurement of CS101 ripples on the power frequency is almost impossible without taking some extra precautions. On the other hand, taken precautions to measure CS101 ripples must not affect the line impedance between the LISN and the EUT and must show high impedance to the test circuit. In this paper, we investigated the CS101 test and possible precautions to be able to measure CS101 ripples under the power frequency. We also focused on how to verify CS101 filters or attenuators, also an entire CS101 test system, just before starting a CS101 test for correct testing.