Programmable IIR bitstream filters

Abstract

This paper presents a compact realization of cascaded biquad digital filters using 2nd order /spl Delta//spl Sigma/ modulators to avoid the need for multibit multipliers. A bit stream biquad is derived with just one /spl Delta//spl Sigma/ modulator for each pair of poles with no significant degradation of sensitivity nor of dynamic range. The proposed structure leads to a straightforward programmable implementation due to its compactness and modularity.