Spectrum analyzer

From Wikipedia, the free encyclopedia

A Rohde & Schwarz FSH3 spectrum analyzer

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 analog and digital spectrum analyzers:

An analog spectrum analyzer uses either 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 or a superheterodyne receiver where the local oscillator is swept through a range of frequencies.
A digital spectrum analyzer computes the Fast Fourier transform (FFT), a mathematical process that transforms a waveform into the components of its frequency spectrum.

Some spectrum analyzers (such as Tektronix's family of "real-time spectrum analyzers") use a hybrid technique where the incoming signal is first down-converted to a lower frequency using superheterodyne techniques and then analyzed using FFT techniques.

1 Acoustic uses
2 See also
3 External links
4 Non-electronic spectrum analyzers

[edit] Acoustic uses

acoustic spectrogram of Tokyo Japanese [minato]

In acoustics, a spectrograph converts a sound wave into a sound spectrogram. The first acoustic spectrograph was developed during World War II at Bell Telephone Laboratories, and was widely used in speech science, acoustic phonetics and audiology research, before eventually being superseded by digital signal processing techniques. Now spectrum analyzers cover the acoustic range.