An Algorithm for Computing Design Parameters of IFIR Filters with Low Complexity

This paper describes an algorithm for computing design parameters of Interpolated FIR (IFIR) digital filters with a low complexity (small number of products per output sample). The interpolation function is performed by a sharpened cascaded Recursive-Running Sum (RRS) filter, where the sharpening technique is used to improve the RRS frequency domain characteristics. Given the desired filter specifications and a chosen sharpening polynomial, the proposed algorithm computes the maximum IFIR filter interpolation factor and the minimum number of stages of the RRS filter in such a way that the overall structure meets the desired specifications with the minimum complexity. Resumen En este artículo se describe un algoritmo para calcular los parámetros de diseño de filtros digitales FIR interpolados