Hardware implementation of FIR/IIR digital filters using integral stochastic computation

Abstract

Stochastic computing (SC) has received much recent attention due to its inherent fault-tolerance and low implementation cost compared to binary radix representations. SC has been proposed for various signal processing applications such as digital filters. The prior art in stochastic FIR filters can accurately implement the desired filtering function for low-order filters, however, their accuracy degrades as the filter order increases. Moreover, stochastic IIR filters demonstrate high hardware complexity and degraded accuracy. In this paper, we propose an architecture for high-order FIR filters with negligible accuracy loss compared to fixed-point implementation. The proposed architecture requires fewer random number generators. We also describe a novel cascaded second-order direct-form II structure for IIR filters. The implementation results of the proposed design show an improvement in latency and hardware complexity compared to the stochastic architectures reported to date.