Multiplier-free FIR filter design based on IFIR structure and rounding

An efficient three-step method for the design of multiplier-free finite impulse response (FIR) filter is presented. In the first step, the desired filter is realized in the form of an interpolated finite impulse response (IFIR) structure consisting of a cascade of a sparse model filter and an interpolator. In the next step, both sub-filters are approximated by rounding of the filter coefficients. In the final step, the sharpening technique is used to improve the overall magnitude characteristics and to satisfy the given specifications