David Middleton and Arthur D. Spaulding

Abstract: New models of electromagnetic interference (EMI) have been developed by Middleton [1-11 ,48,49] over the last decade (1974–1983), which have provided canonical, analytically tractable, and experimentally well established quantitative descriptions of nearly all EMI environments. These models are (1) physically derived; (2) are canonical in the sense that they are invariant of the nature and waveform of the source and details of propagation, as far as their formal anaIytical structure is concerned; (3) are highly non-Gaussian; and (4) are analytically and computationally manageable. Their principal quantitative and most widely applied form is embodied in the first-order probability distributions of the (instantaneous) amplitude, and envelope, of the received waveform following the linear front-end stages of a typical receiver. Three basic EMI models are distinguished: Class A, B, and C, respectively involving sets of three, six, and eight physically derived parameters, which are measurable from observed EMI amplitude (or envelope) data. These three basic classes are defined in terms of receiver bandwidth vis-à-vis that of the EMI. When receivers conventionally optimized for Gauss noise (i.e., matched-filter systems) are used in these highly non-Gaussian EMI environments, receiver performance can be greatly degraded [0(20-40 dB), typically], vis-à-vis that of receivers optimized to the actual EMI in force (e.g., Class A, B, or C noise) [2,13,14,21]. Specific examples of this behavior are provided. The physical bases and practical implications of the EMI models themselves and their impact on the reception process also are discussed. The principal aim of this Report is to present a Tutorial Review of the main features of the work to date (≤ 1985) on these models and their current and potential applications, particularly for weak-signal detection. Accordingly, this Report represents an updated and expanded version of an earlier tutorial review ([40], 1980). Various analytical details are reserved to an Appendix, and the full technical analysis and results are specifically cited in the extensive list of references, which themselves are briefly appraised from the viewpoint of the reader’s further interest.

Keywords: electromagnetic interference environments (EMI); class A, B, C noise; optimum and suboptimum detectors; optimum signal detection; performance comparison

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