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ifft
Inverse one-dimensional fast Fourier transform
y = ifft(X) y = ifft(X,n) y = ifft(X,[],dim) y = ifft(X,n,dim)
y = ifft(X)
returns the inverse fast Fourier transform of vector X.
If X is a matrix, ifft returns the inverse Fourier transform of each column of the matrix.
If X is a multidimensional array, ifft operates on the first non-singleton dimension.
y = ifft(X,n)
returns the n-point inverse fast Fourier transform of vector X.
y = ifft(X,[],dim)
and y = ifft(X,n,dim) return the inverse discrete Fourier transform of X across the dimension dim.
For any x, ifft(fft(x)) equals x to within roundoff error. If x is real, ifft(fft(x)) may have small imaginary parts.
The algorithm for ifft(x) is the same as the algorithm for fft(x), except for a sign change and a scale factor of n = length(x). So the execution time is fastest when n is a power of 2 and slowest when n is a large prime.
dftmtx, freqz, specplot, and spectrum in the Signal Processing Toolbox, and:
fft One-dimensional fast Fourier transform
fft2 Two-dimensional fast Fourier transform
fftshift Move zero'th lag to center of spectrum.