Implementation of LMS-ALE Filter using Vedic Algorithm

Jintu K Joseph Purushotham U

doi:10.4172/2168-9679.1000237

Abstract

ALE or adaptive line Enhancers are special kinds of adaptive filters widely used in noise cancellation circuits. In circuits where we don’t have any prior knowledge of signal and noise, fixed filters unit never works good. Among adaptive filter ring algorithms LMS algorithm is very common, in our work also we use LMS algorithm. LMS-ALE filters removes the sinusoidal noise signals present in the channel by calculating the filter coefficients in every iteration. LMS-ALE filter has large number of multiplier units. FFT or Fast Fourier Transform blocks present in LMS algorithm again consist of large array of multiplier units. Optimization of LMS-ALE filter lies must start from optimization of multiplier blocks. Here we use Vedic “Vertical and crosswise algorithm” for multiplier design. When compared to conventional booth multiplier based LMS-ALE filter units, Vedic multipliers gives more performance in areas like resource utilization, power requirement, delay etc. The work includes designing Vedic multipliers, complex Vedic multipliers, redesigning Radix-8 FFT using Vedic multipliers, redesigning LMS block using Vedic FFT, redesigning LMS ALE filter using Vedic multipliers and Vedic LMS blocks. Major part of design is done in Verilog using Xilinx ISE design suite. ADC block present in LMS-ALE filter is done in Matlab version 2013.

Highlights

In physical environment noise is automatic signal, in all kinds of signal generated there is some kind of unwanted noise signals, when such a signal is amplified in a communication channel both noise and desired signal gets amplified it reduces the clarity of communication system, noise cancellation is inevitable
ALE Filter is a most common noise cancellation system. It uses some kind of adaptive algorithm [LMS algorithm]
In this work a generic N x N bit Vedic multiplier which can perform both signed and unsigned multiplication are designed in Xilinx using Verilog

Summary

Introduction

In physical environment noise is automatic signal, in all kinds of signal generated there is some kind of unwanted noise signals, when such a signal is amplified in a communication channel both noise and desired signal gets amplified it reduces the clarity of communication system, noise cancellation is inevitable. ALE Filter is a most common noise cancellation system. It uses some kind of adaptive algorithm [LMS algorithm]. LMS adaptive block consist of FFT and inverse FFT blocks as it handles the signal in frequency domain. Multipliers are the most repeated block in LMS-ALE filter, to optimize the performance we need to do the optimization from basic multiplier block. In this work we use Vedic algorithm for doing the multiplication

Methods

Results

Conclusion