Editing Spectrum analyzer (section)

{{Short description|Electronic testing device}}
[[Image:Spektrumanalysator FSL von Rohde & Schwarz.jpg|right|thumb|A spectrum analyzer from 2005]]
[[File:A modern real time spectrum analyzer.jpg|thumb|A modern real time spectrum analyzer from 2019]]

A '''spectrum analyzer''' measures the magnitude of an input signal versus frequency within the full frequency range of the instrument. The primary use is to measure the power of the spectrum of known and unknown signals. The input signal that most common spectrum analyzers measure is electrical; however, [[Frequency spectrum|spectral]] compositions of other signals, such as acoustic pressure waves and optical light waves, can be considered through the use of an appropriate [[transducer]]. Spectrum analyzers for other types of signals also exist, such as optical spectrum analyzers which use direct optical techniques such as a [[monochromator]] to make measurements.

By analyzing the [[Frequency spectrum|spectra]] of electrical signals, dominant frequency, [[electric power|power]], [[distortion]], [[harmonics]], [[Bandwidth (signal processing)|bandwidth]], and other spectral components of a signal can be observed that are not easily detectable in [[time domain]] [[waveform]]s.  These parameters are useful in the characterization of electronic devices, such as wireless transmitters.

The display of a spectrum analyzer has ''frequency'' displayed on the horizontal axis and the ''amplitude'' on the vertical axis. To the casual observer, a spectrum analyzer looks like an [[oscilloscope]], which plots ''amplitude'' on the vertical axis but ''time'' on the horizontal axis. In fact, some lab instruments can function either as an oscilloscope or a spectrum analyzer.