DSP implementation of fast FIR filtering algorithms using short FFT´s

This paper proposes an efficient implementation of fast FIR filtering algorithms with useful characteristics for real-time application. They maintain a low processing delay, independent of the filter length. The difficulty is to keep as much as possible of the improvement brought by the reduction of the arithmetic complexity of these fast FIR filtering algorithms without exceeding the Digital Signal Processor (DSP) resources (number of registers, pointers, memory, ...). A particular attention is devoted to the heavy use of pointers which represents a crucial problem. It is solved in this paper by an optimal organisation of data in memory. Improvements of more than 70% in actual timings on an ADSP-2100 compared to the classical algorithm of convolution are obtained, even for very short blocks