Overlapped block digital filtering

Block digital filtering has been suggested to increase the parallelism of computation and to reduce the computational complexity of digital filtering systems. In this paper the block processing concept is generalized by considering overlapped input and/or output blocks. As an overlapped block digital filter is, in general, a shift-varying system, the conditions for its shift-invariant operation have been developed. These conditions have been exploited to derive computationally efficient shift-invariant block structures. Two types of fast FIR filtering algorithms using the overlapped block filter structures are derived. One is based on the adaptation of fast short-length linear convolution algorithms and the other is based on DFT algorithms. These algorithms not only reduce the computational complexity of filtering operations but also offer modular and parallel structures. Finite wordlength effects of FIR filters implemented using the overlapped block filter structure are also investigated