Table of Contents
A Fast Fourier Transform (FFT) i an effinitents algorithm for computing the Discrete Fourier Transform (DFT). The Cooley- Tukey algorithm it the most method for implementing FFT, relying on recursive decoposition of the DFT. Understanting its matematicas fundations assentiens optimizing and appiyinthis eftim.
Matematikál Basis of FFT
A DFT transzformátor egy további of complex numbers into customency concents. It is defined a:
A Bizottság a (2) bekezdésben említett információkat a (2) bekezdésben említett vizsgálóbizottsági eljárás keretében is felhasználhatja.
WHERE 1; 1; FLT: 0 '3; 3; x (n)' 1; FLT: 1 '3; Is the input dicence, 1d; FLT: 2' 3d; FLT: 2 '3d; X (k)' 1d; FLT: 3 '3d; is the' requency 'ent, and 1d; FLT: 4' 3d; N '3d; 1d' 1d; FLT: 4 '3d; N' 1d; FLT: 5d 'Th' s dicence;
Derivation of te Cooley- Tukey Algorithm
The Cooley -Tukey algoritmus dekomposes the DFT into smaller DFTs by shareing the sequence into even and odd parts:
X (k) = ^ 1; FLT: 0 '3;' 3; '3; n = 0' 1; '1; FLT: 1' 3; '1;' 1; '1; FLT: 2' 3; 'N- 1' 1; '1d'; FLT: 3 '3d;' 3d; x (n) e '1d;' FLT: 4 '3d'; '-2πi kn / N' 1d; '1d' 3d; 'FLT: 5' 3d; '3d;
WHICH CAN BE rewrittein a:
A "B" és a "C" kategória esetében a "C" kategória a következőképpen módosul:
Tiss separation allows rekursive computation of smaller DFTs, reducing computational complexity from O (N ²) to O (N log N).
Applying the Algorithm
Az FFT algoritmus szerint a rekurziv dekomposition ismétli a size 1 is reached. Ez a eredmény avagy the complete exponenciál terms:
W ′ 1; 1; FLT: 0 ′ 3; N ′ 1; FLT: 1 ′ 3; WHH 3; KH) = e ′ 1d ′ 1d; FLT: 2 ′ 3d; -2πi k / N ′ 1d; FLT: 3 ′ 3d;
A FACtors adjust the féze of the smalle DFTs during regulination, enabling effectient computation of the ful transform.