IMPLEMENTAÇÃO DE ARQUITETURA DEDICADA DE FILTRO ADAPTATIVO EM CODIFICAÇÃO HÍBRIDA UTILIZANDO O ALGORITMO LMS

Abstract

This work proposes the implementation of dedicated hardware architecture for the Least Mean Square (LMS) adaptive filtering algorithm by using Hybrid encoding, whose main goal is to cancel the interferences in the signal of interest. In the used scheme, from a 60Hz reference signal, the algorithm is able to estimate the superior harmonics, using after these results for the cancelling of interferences related to the signal of interest. One of the techniques that is widely used for the switching activity reduction uses signal encoding. In this work, the proposed adaptive filtering architecture uses the Hybrid encoding in its data buses, whose main idea is to split the operands in group of m-bits, encode each group using the Gray code (that potentially enables reduction of the switching activity into each group) and propagate the carry between the groups as in the Binary encoding. We developed new Hybrid multipliers for signed multiplication, which uses radix-2m encoding. The multipliers are applied to the adaptive filtering architecture. We have implemented 18, 23 and 36 bit-width radix-4 Hybrid array multipliers, as well as a particular case for the radix-8 (m=3) operation. The main results showed that the Hybrid multipliers are more efficient than the Binary ones, by presenting less power consumption in some cases. Moreover, the implemented adaptive filtering architectures were validated and compared in both Binary and Hybrid encoding. The efficiency of the implemented filters for the cancelling of interferences was proved by using both encoding scheme. By the presented results, we conclude that it could be practicable to implement an adaptive filtering architecture operating on Hybrid encoding