BASIC SIGNAL PROCESSING SYSTEM DESIGN ON FPGA USING LMS BASED ADAPTIVE FILTER

Abstract

Adaptive digital filter based on LMS algorithms widely used in the area of digital signal processing to iteratively estimate the statistics of an unknown signal. Design of an adaptive filter is based on three major computing elements namely multiplier, adder and delay unit torealize the Finite Impulse Response (FIR) filter. The filter weights( coefficient) of the FIR filter are adjusted automatically by Least Mean Square of the error so as to match the adapted output to the desired input. This paper explains the design of adaptive filter by two approaches. One is model based approach and other is Field Programmable Gate Arrays (FPGAs). The model based design approach is developed around MATLAB, SIMULINK and SYSTEM GENERATOR tools, which provide a virtual FPGA platform. Modern FPGA include the resources needed to design efficient filtering structures. The LMS algorithm has been implemented on CYCLONE II EP2C35F672C8 FPGA device, using ALTERA QUARTUS II development platform. The three major demonstrable applications cited in the present work are System Identification, Noise reduction and Echo cancellation.