fft

Fast Fourier transform.

📝 Syntax

• Y = fft(X)

• Y = fft(X, n)

• Y = fft(X, n, dim)

📥 Input argument

• X - a vector, matrix or N-D array (double, single, integer, logical).

• n - transform length: a non negative integer scalar or [] (default).

• dim - dimension: a positive integer scalar.

📤 Output argument

• Y - a vector, matrix, N-D array: frequency domain representation.

📄 Description

fft(X) computes the discrete Fourier transform of X using a Fast Fourier Transform (FFT) algorithm based on FFTW library.

💡 Example

 % Sampling frequency
Fs = 150;

% Time vector of 1 second
t = 0:1*inv(Fs):1;

% Creates a sine wave of f Hz.
f = 5;
x = sin(2 * pi * t * f);

% Length of FFT
nfft = 1024;
% Take fft, padding with zeros so that length(X) is equal to nfft
X = fft(x, nfft)
% FFT is symmetrix
X = X(1:nfft*inv(2))

% Frequency vector
f = (0:nfft *inv(2) -1)*Fs * inv(nfft);

🔗 See also

ifft, fftw.

🕔 History

Version	📄 Description
1.0.0	initial version