Eigenvectors and functions of the discrete Fourier transform
Bruce Dickinson, Ken Steiglitz · IEEE Transactions on Acoustics Speech and Signal Processing · 1982
A method is presented for computing an orthonormal set of eigenvectors for the discrete Fourier transform (DFT). The technique is based on a detailed analysis of the eigenstructure of a special matrix which commutes with the DFT. It is also shown how fractional powers of the DFT can be efficiently computed, and possible applications to multiplexing and transform coding are suggested.