A spectrum analyzer is a device used to examine the spectral composition of some electrical, acoustic or optical waveform.

Often, it measures the power spectrum.

There are analogue and digital spectrum analyzers:

• An analogue spectrum analyzer uses basically a variable bandpass filter whose mid-frequency is automatically tuned (shifted, swept) through the range of frequencies of which the spectrum is to be measured.
• A digital spectrum analyzer uses fast Fourier transform (FFT), a mathematical processes transforms a waveform into its compositions of frequencies in the spectrum. As a result, computer programs can compute such transforms, and makes audio processing easier. FFTs have applications in much wider fields.

See also

electromagnetic spectrum, spectrum, spectrogram, spectrum analyzer

Utilized in measure atomic particals.