Design of direct-form FIR digital filters with discrete valued coefficients

The authors present a simple method for designing direct-form FIR (finite impulse response) digital filters with discrete valued coefficients. First, standard packages are used to design infinite precision (IP) filters. The coefficients of IP filters are then quantized to the given wordlength in such a way that the resulting zero deviation due to the quantization is kept at the lowest level possible. An iterative algorithm is presented to find the discrete valued coefficients which is (at least locally) optimal in the sense of minimum zero deviation, requiring minimal computations. Design examples are provided to show that this algorithm works extremely well and is able to deal with long filters very effectively