A matrix theory proof of the discrete convolution theorem
B.R. Hunt · IEEE Transactions on Audio and Electroacoustics · 1971
In this paper we prove the discrete convolution theorem by means of matrix theory. The proof makes use of the diagonalization of a circulant matrix to show that a circular convolution is diagonalized by the discrete Fourier transform. The diagonalization of the circular convolution shows that the eigenvalues of a circular convolution operator are identical with the discrete Fourier frequency spectrum.