Spectrum analyzer is used to study signal distortion, modulation, spectral purity, frequency measurement stability and inter modulation distortion signal parameters. It also can be used to measure some parameters of amplifier and filter circuitry, which is a versatile electronic measuring instruments. It is also called frequency domain oscilloscope, analyze oscilloscope, harmonic analyzer, etc.

Modern spectrum analyzers can display the results of the analysis in analog or digital mode. If the interior of the instrument uses digital circuits and microprocessors, it will have storage and computing functions; it is easy to constitute a test system with the configuration standard interface.