1. Fourier transform. FFT. FFT

Preliminaries. Notations

A Fourier transform-based signal analyzer provides time and frequency, or even time-frequency, information on the signal applied to it, by digitally processing the signal . If the signal analyzer only provides spectral characteristics, it is often referred to as a spectrum analyzer.

Although digital processing itself can be envisaged without explicit recourse to the notions of time and...