A method to optimize the direction and measurement of EMI signals

The detection and measurement of electromagnetic interference (EMI) signals using conventional EMI receivers and spectrum analyzers is discussed. A statistical approach is used to demonstrate that the probability of detecting a single signal increases as the receiver sweep rate increases. This is then demonstrated in the more general case of multiple signals. Signal density is defined by the Poisson random variable, and an equation is derived that relates the probability of detection to signal density and receiver sweep rate. Also discussed is the choice of types of receivers and detectors that will ensure a maximum probability of detection. A sequential process that first detects signals with a high degree of probability and then performs an accurate measurement of their amplitude and frequency is described