The Fast Fourier Transform as a Signal Processing Technique.

The proliferation of digital equipment for use in making all types of measurements has necessitated drastic changes in the signal detection techniques used to quantify measured signals. More specifically, there has been an increased use of the kinds of digitizers whose output consists of sequential time slices of the measured signal in binary coded values that correspond to amplitude and time. This type of information is directly transferrable to a computer memory, where it can be processed by a wide variety of digital techniques. One of the most useful digital processes used to resolve amplitude and phase spectra from a digitized time-domain signal is the fast Fourier transform FFT. This document attempts to give the reader a sound understanding of what the FFT does and how it can be applied to various measurement needs. Author