Fast algorithms for generalized discrete Hartley transform of composite sequence lengths

This paper presents fast algorithms for type-II, type-III, and type-IV gene ralized discrete Hartley transform. In particular, new odd-factor algorithm s are derived to support transforms whose sequence length contains multiple odd factors. By jointly using the odd-factor and radix-2 algorithms, fast computation for arbitrarily composite sequence length can be achieved. Comp ared to other reported algorithms, the proposed ones have a regular computa tional structure, achieve a substantial reduction of computational complexi ty, and support a wider range of choices on the sequence length.