FIR filter hardware reduction with adaptive delta-modulation

This paper presents a new type of digital system which makes use of adaptive delta-modulation for input digitization and is particularly suited to the hardware implementation of small, low power, programmable digital filters. An experimental prototype was built which demonstrated a finite impulse response (FIR) digital filter. This filter has no requirement for hardware multipliers and has a significant reduction in input sample storage capacity when compared to equivalent pulse code modulation (PCM) filters. Quantitative as well as qualitative results show that this new filter is especially useful with voice inputs.