LOW-POWER DIGITAL FILTERING USING APPROXIMATE PROCESSING

We present an algorithmic approach to the design of low-power frequenc y-selective digital filters based on the concepts of adaptive filterin g and approximate processing. The proposed approach uses a feedback me chanism in conjunction with well-known implementation structures for f inite impulse response (FIR) and infinite impulse response (IIR) digit al filters; Our algorithm is designed to reduce the total switched cap acitance by dynamically varying the filter order based on signal stati stics. A factor of 10 reduction in power consumption over fixed-order filters is demonstrated for the filtering of speech signals.