|Signal Processing Toolbox|
Discrete Fourier transform matrix
A discrete Fourier transform matrix is a complex matrix of values around the unit circle, whose matrix product with a vector computes the discrete Fourier transform of the vector.
n complex matrix
A that, when multiplied into a length
n column vector
computes the discrete Fourier transform of
The inverse discrete Fourier transform matrix is
In practice, the discrete Fourier transform is computed more efficiently and uses less memory with an FFT algorithm
than by using the Fourier transform matrix.
dftmtx takes the FFT of the identity matrix to generate the transform matrix.