Studying the Probability of EMI through Time-Variance Behavior of Environment on Medical Devices

The electromagnetic environment in buildings is complex and fluctuating in time. We can distinguish three time scales: short, mid and long term time-variance. In this paper we measure the time-varying behavior of a complex electromagnetic environment over the course of a 24-hour period. We show that this measurement provides extra information on top of short time-variance data, necessary to assess the risk for EMI in a complex EM environment; the risk-based EMC approach.