Electromagnetic compatibility is the ability of electrical equipment to operate as intended in its electromagnetic environment without causing unacceptable disturbance to other equipment. Emission and immunity are complementary questions: how strongly does a device disturb its surroundings, and how well does it tolerate disturbances arriving from them?
Interference requires a source, a coupling path and a susceptible receiver. A switching power converter may couple a disturbance into a sensor through shared supply impedance, capacitive coupling or radiated fields. In an illustrative circuit, a A switching-current change through a shared return impedance produces a mV reference shift, potentially much larger than the sensor signal. A balanced connection and finite common-mode rejection ratio help only to the extent that the disturbance remains common to the two inputs.
A useful test compares the sensor output with the converter switched on and off, then deliberately changes the coupling path or applies a calibrated disturbance. Antenna patterns, cable routing, grounding and frequency all enter the inference; passing one test configuration does not imply immunity to every disturbance.[ref]
Antenna Models for Electromagnetic Compatibility Analyses by C. W. Wang and T. Keech. Executive summary, antenna parameters and electromagnetic-interference analyses
Articles by others on the same topic
Electromagnetic Compatibility (EMC) refers to the ability of electronic devices and systems to function properly in their electromagnetic environment without causing or experiencing interference. It encompasses two primary aspects: 1. **Emissions:** This aspect deals with how much electromagnetic energy (in the form of noise or interference) a device emits into the environment. Devices must comply with regulations that limit the amount of electromagnetic interference (EMI) they can generate to avoid disrupting other electronic devices.