Improving area efficiency of FIR filters implemented using distributed arithmetic

In this paper we present techniques for improving area efficiency of FIR filters implemented using the distributed arithmetic (DA) approach. These techniques exploit the flexibility in partitioning the filter coefficients for a two lookup-table (LUT) based DA implementation. The first technique is targeted at a ROM based implementation of LUTs and aims at minimizing number of columns/outputs of the ROMs. The second technique is targeted at a hardwired implementation of LUTs. We have developed an estimation technique for relative area comparisons of hardwired LUTs having the same number of inputs and outputs. We present a heuristic approach, based on this estimation technique, to optimally partition coefficients so as to achieve area-efficient hardwired implementation of LUTs. We present results to show these techniques can result in 10% to 15% area reduction for ROM based implementations and 20% to 25% area reduction for hardwired implementations.