Title: Fast Fourier-Hadamard decoding of orthogonal codes
Abstract: Posner (1968) has recently discussed a decoding scheme for certain orthogonal and biorthogonal codes which is based on the fast Fourier transform on a finite abelian group. In this paper, we present an alternate approach to this problem based on the direct product of matrices. This approach is easily understood by anyone familiar with matrix theory, and it yields results in a form convenient for implementation and generalization.