The discrete Fourier transform: A canonical basis of eigenfunctions

Abstract

The discrete Fourier transform (DFT) is an important operator which acts on the Hilbert space of complex valued functions on the ring Z/NZ. In the case where N=p is an odd prime number, we exhibit a canonical basis of eigenvectors for the DFT. The transition matrix from the standard basis to the canonical basis defines a novel transform which we call the "discrete oscillator transform" (DOT for short). Finally, we describe a fast algorithm for computing the DOT in certain cases.

To appear in the proceeding of the 2008 European Signal Processing Conference (EUSIPCO-2008), Lausanne, Switzerland; MSC classifications: Fourier transform, Weil representation, symmetries, eigenfunctions, oscillator transform, fast oscillator transform