Questions about the use and theory of spectrum analyzers. For spectrum displays that are not test equipment, use [panadapter-and-waterfall] instead.

A spectrum analyzer is RF test equipment which displays the amount of RF power versus frequency received on its input ports. Spectrum analyzers may operate on the principle of automatically sweeping a receiver across the desired display range of frequencies, or by performing a discrete Fourier transform on the entire bandwidth to be visualized.

A tracking generator is a component of a spectrum analyzer which produces a swept signal in sync with the frequency the spectrum analyzer is currently receiving; this is one method to test the frequency response of filters and other RF components.

See also for the similar but often less precise instruments incorporated into radio receivers to find and view signals.