# Fourier transform

## Description

A complex mathematical function that converts a time-based function, called an interferogram, into a distance-based function, called a spectrum. An interferogram is generated using an interferometer. An interferometer uses the differences between a moving mirror and a fixed mirror to modulate a radiation source, thereby allowing all wavelengths to be measured at once. This increases the effective signal intensity and thus increases the measurement sensitivity. Fourier transforms are used for several spectroscopic analytical methods such as infrared (IR), raman and nuclear magnetic resonance (NMR).

## Synonyms and Related Terms

Fourier-Transformation (Deut.); transformée de Fourier (Fr.);