Energy efficient filtering using adaptive precision and variable voltage

A Finite Impulse Response (FIR) filter architecture based on a Distributed Arithmetic (DA) approach with two supply voltages and variable bit precision operation is presented. The filter is able to adapt itself to the minimum bit precision required by the incoming data and also operate at a lower voltage so that it still meets a fixed throughput constraint. As opposed to the worst case fixed precision design, our precision-on-demand implementation has an energy requirement that varies linearly with the average bit precision required by the input signal. We also demonstrate that 50% to 60% energy savings can easily be obtained in the case of speech data