Fast algorithm for computing cosine number transform

A fast algorithm for the computation of a cosine‐like number‐theoretic transform is presented. The method, which corresponds to a finite field extension of a method originally designed for computing real‐valued discrete cosine transforms, is recursive and suitable for VLSI implementation. A general flow diagram for the proposed algorithm is given and shows that, in some specific cases, it can be evaluated using additions and bit‐shift operations only.