[Matlab]自编FFT运算验证
差点被下标搞晕了,matlab下标从1开始,而X(k)和r下标从0开始。
http://www.ilovematlab.cn/forum.php?mod=viewthread&tid=545743&page=1&extra=#pid3399877
理论基础:
实现代码:
clear; clc; close all; N = 8; xn = [ 4 3 2 6 7 8 9 0 ]; G = zeros(1,N/2); H = zeros(1,N/2); for i = 0: N/2 - 1 k = i+1; for r = 0 : N/2 - 1 G(k) = G(k) + xn(2*r+1)*w_nk( N / 2 ,r*i); H(k) = H(k) + xn(2*r+2)*w_nk( N / 2 ,r*i); end end X = zeros(1,N); for i = 0:N/2 -1 k = i+1; X(k) = G(k) + w_nk(N,i)*H(k); X(k+N/2) = G(k) - w_nk(N,i)*H(k); end Xk = fft(xn,8); f = 0:7; figure(1); subplot(2,2,1); stem(f,abs(X)); title('自编FFT-幅度谱'); subplot(2,2,2); stem(f,abs(Xk)); title('库FFT-幅度谱'); subplot(2,2,3); stem(f,angle(X)); title('自编FFT-相位谱'); subplot(2,2,4); stem(f,angle(Xk)); title('库FFT-相位谱');
验证结果:
~不再更新,都不让我写公式,博客园太拉胯了