Examination of electronic module immunity using transfer functions

In this paper, the immunity of electronic modules to external electromagnetic interference (EMI) was evaluated using transfer functions, which correlate the external disturbances with the noise encountered by the components inside the module. Simple lumped-circuit models are used to describe noise coupling mechanisms, and they can be verified by straight-forward test procedures. Based on these simple models, the dominant coupling mechanisms were identified and mitigation effectiveness verified. This approach was utilized to examine an electronic module with immunity weaknesses. The module was first studied on-bench, at no power. Counter measures were then applied and effectiveness quantified. This component was then tested on a functional vehicle, with measured effectiveness matching on-bench predictions flawlessly.