Hi! I can get the correct frequency value from below code: Fs = 100; n = 1/Fs:1/Fs:2; x = 0.8*sin(2*pi*10*n); z = fft(x); N = length(z); z = abs(z(1:N/2+1)); freq = [0:N/2]/N*Fs; stem(freq,z);grid;zoom on; but, when I use fft(x,N) -- N=2^k, who can I get the correct frequency value? Thanks! |