Efficient Parallel Architecture for Fixed-Coefficient and Variable-Coefficient FIR Filters Using Distributed Arithmetic

Abstract

In this paper, we performed the complexity analysis of fixed-coefficient and variable-coefficient distributed arithmetic (DA)-based finite impulse response (FIR) filter structures to observe the effect of LUT decomposition on the area complexity of DA structure. The complexity analysis reveals that the area complexity of different units of DA FIR filter structure does not increase proportionately with the level of parallelism. An appropriate selection of LUT decomposition factor, and introducing higher level of parallelism in the computation could improve the area-delay efficiency of both fixed-coefficient and variable-coefficient DA-based FIR structures. Based on these findings, we have proposed bit-parallel block-based DA structures, for fixed-coefficient and variable-coefficient FIR. The proposed structures process one block of input samples and produce one block of outputs in every clock cycle. Theoretical estimate shows that the proposed fixed-coefficient structure, for block-size 8 and filter-length 32, involves eight times more ROM-LUT words, eight times more adders, two less registers, and offers eight times higher throughput-rate than the existing similar structure. For the same block-size and filter-length, the proposed variable-coefficient structure involves 7.2 times more adders, the same number of registers, eight times more MUXes, and offers eight times higher throughput than the best available similar structure. Synthesis result shows that the proposed fixed-coefficient structure for block-size 8 and filter-length 32 involve 47% less area delay product (ADP) and 42% less energy per sample (EPS) than the existing structure and offers nearly eight times higher throughput than others. For the same block-size and filter-length, the proposed structure for variable-coefficient FIR involves 71% less ADP and 65% less EPS than the similar existing structures.