fftshift - Shift zero-frequency component to center of spectrum
最编程
2024-08-14 14:35:14
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You can process multiple 1-D signals by representing them as rows in a matrix. Then use the dimension argument to compute the Fourier transform and shift the zero-frequency components for each row.
Create a matrix A whose rows represent two 1-D signals, and compute the Fourier transform of each signal. Plot the power for each signal.
fs = 100; % sampling frequency t = 0:(1/fs):(10-1/fs); % time vector S1 = cos(2*pi*15*t); S2 = cos(2*pi*30*t); n = length(S1); A = [S1; S2]; X = fft(A,[],2); f = (0:n-1)*(fs/n); % frequency range power = abs(X).^2/n; % power plot(f,power(1,:),f,power(2,:))
Shift the zero-frequency components, and plot the zero-centered power of each signal.
Y = fftshift(X,2); fshift = (-n/2:n/2-1)*(fs/n); % zero-centered frequency range powershift = abs(Y).^2/n; % zero-centered power plot(fshift,powershift(1,:),fshift,powershift(2,:))
