Efficient moving-window DFT algorithms

The authors deal with the real-valued, moving-window discrete Fourier transform. After reviewing the basic recursive versions appearing in the literature, additional recursive equations are presented. Then, these equations are combined so that nonrecursive expressions involving only consecutive discrete Fourier transform (DFT) sine components are obtained for both the DFT cosine component and squared harmonic amplitude. The computational complexity of this new scheme is finally studied and compared to that of existing methods, showing that, in most practical situations, a reduction in the operation count is achieved