Hardware Approach of a Multipurpose Finite Impulse Response Filter for Real-Time Filtering Applications

Amin Amin

doi:10.3844/ajassp.2011.1272.1281

Abstract

Problem statement: Finite Impulse Response (FIR) filters are widely u sed in various DSP applications. The design of digital FIR filters is a very basic problem in digital signal processing. A FIR filter with multiple operation capability is ce rtainly very useful for any real-time filtering applications. This article presents a multipurpose FIR filter design modeled by the hardware description language VHDL for real-time filtering a pplication. Approach: The VHDL has its concept of concurrency to cope with the parallelism of digi tal hardware. The novel feature is the capability o f the design to accomplish up to 127variable filter o rder and an arbitrary filter frequency response. Th e coefficients are calculated by Hamming windowing technique. Basing on selection embedded in the design, the model is able to execute highpass, lowp ass, bandstop and bandpass filtering operations. It is set at 8-bit signed data processing. To filter t he input data in time domain, Linear Constant Coefficient Difference Equation (LCCDE) is used by the filter. Results: The design outputs are validated through simulation and compilation. The o utput results are also compared with the MATLAB implemented calculated output results to test the correctness that proves the effectiveness of the design. Conclusion: With the capability of filtering signal in real ti me mode utilizing arbitrary filter shape, the multipurpose filter proves to be versatile.

Highlights

Frequency-sensitive linear filters can be divided into two categories: Finite Impulse Response filters (FIR) and Infinite Impulse Response filters (IIR)
In this study we present a model of multipurpose FIR filter by hardware description language VHDL
Low pass and band pass in the MATLAB and such, the data is read line by line from the text file

Summary

Introduction

Frequency-sensitive linear filters can be divided into two categories: Finite Impulse Response filters (FIR) and Infinite Impulse Response filters (IIR). The design of FIR digital filters is a very basic problem in digital signal processing. A lot of attention for the last 30 years has been received in this field. It is widely used in various DSP applications. The FIR filter is chosen for applications which require linear phase or where not producing noise inside the filter is vital. True linear phase can be achieved only in an FIR filter where the impulse response is symmetric. Filters without noise can be achieved only with FIR filters. Because FIR filters can always be designed with a sufficient number of bits in the multipliers where truncation or rounding is not required after the multiplication. In the arena of digital FIR filters designing with the constant fixedpoint binary coefficients, significant work has been done (Ma and Taylor, 1990; Lim and Liu, 1988; Dey and Oppenheim, 2008)

Objectives

Results

Conclusion