- Techniques for Measuring Narrowband and Broadband Emi Signals Using Spectrum Analyzers

The versatility of spectrum analyzers allows electromagnetic interference (EM1) signals to be displayed in a variety of ways for the analysis of specific signal characteristics. Two signal types of particular interest are those classified as narrowband (NB) and broadband (BB) signals. These signals originate from a variety of sources and have different EMl potential. This paper first provides defini tions for NB and BB signals and discusses the difficul ties involved in measuring each type. The second part of the paper explains how spectrum analyzer controls and detection modes can be used to characterize signals as NB or BB. Finally, commonly-used methods for discriminating between NB and BB signals in both commercial and mili tary testing are discussed, and the implementation of these methods using a spectrum analyzer is described. AUTHORS: Siegfried Linkwi tz, R&D Section Manager, HP Signal Analysis Division, Rohnert Park, CA. Dipl. Ing., Hochschule Darmstadt, 1961. Worked as development engineer on HP RF signal generators, microwave sweepers and network analyzers, then as project manager for the HP 8566A Spectrum Analyzer. Now studying applications of spectrum analyzers for diagnostic and compliance testing of EM1. Al Wilcox, Application Engineer, HP Signal Analysis Division, Rohnert Park, CA. BSEE University of Washington, 1970. Joined HP in 1972 as a micro-electronics engineer doing thin-film design. In Marketing since October, 1981, concentrating on EMC measurement techniques.