This document discusses algorithms for the Fast Fourier Transform (FFT). It describes the Decimation in Time (DIT) and Decimation in Frequency (DIF) categories of FFT algorithms. Specifically, it outlines the Radix-2 DIT-FFT algorithm, which decomposes an N-point sequence into even and odd samples, obtaining the N-point discrete Fourier transform from the discrete Fourier transforms of the two smaller sequences, reducing arithmetic operations. It further explains that in DIT, the sampling interval is decimated by a factor of two at each stage when calculating the N-point discrete Fourier transform starting from two-point transforms.