Hardware-efficient FIR filters with reduced adder step

A technique for reducing the hardware complexity of constant coefficient finite impulse response (FIR) digital filters, without increasing the number of adder steps in the multiplier block adders, is presented. The filter coefficients are adjusted so that the number of full adders in the hardware implementation of any coefficient is independent of the coefficient wordlength and the number of shifts between nonzero bits in the coefficient. Results show that the proposed technique achieves a significant reduction in both the multiplier block adders and the multiplier block full adders when compared to existing techniques.