International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395 -0056 Volume: 04 Issue: 03 | Mar -2017
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p-ISSN: 2395-0072
TRANSPOSE FORM FIR FILTER DESIGN FOR FIXED AND RECONFIGURABLE COEFFICIENTS Ariprasath.S*1,Dr.C.Santhi2 1Pg
scholar, Dept of ECE, Government College of Technology, Coimbatore, Tamilnadu, India professor, Dept of ECE, Government College of Technology, Coimbatore, Tamilnadu, India ---------------------------------------------------------------------***--------------------------------------------------------------------2Associatet
Abstract -Transpose form finite impulse response (FIR) filter is naturally a pipelined structure which supports the multiple constant multiplications (MCM) technique but direct form FIR filter structure does not support MCM technique. The MCM is more effective in Transpose form when the common operand is multiple with the set of constant coefficients that reduce the computational delay. The implementation of MCM technique is easier in fixed coefficient Transpose form FIR filter but complex in reconfigurable coefficients. In fixed coefficients transpose FIR filter, area and delay are reduced by using MCM technique. The low-complexity design using the MCM technique is implemented for fixed coefficients transpose form FIR filters and multiplier-based design is used for reconfigurable transpose form FIR filter. The implemented transpose form FIR filter structure achieved less area and delay than the direct-form FIR filter structure. The XILINX software tool is used for simulation.
configurations, namely direct form FIR filter and transposes form FIR filter. The Transpose form FIR filter can be constructed from the direct form FIR filter by Exchanging the input and output and inverting the direction of signal flow.Generally,Transpose form FIR filters are support multiple constant multiplications (MCM) technique that results in saving of computation time. Transpose form finite-impulse response (FIR) filters are inherently pipelined and support multiple constant multiplications (MCM) technique that results in significant saving of computation. However, transpose form configuration does not directly support the block processing unlike direct form configuration. Generally,Transpose form FIR filters are support multiple constant multiplications (MCM) technique that results in saving of computation time. TheMCM is an arithmetic operation that multiplies a set of fixed-point constants (Example: H0, H1, H2,…., Hn) with the same fixed-point variable (X).
Key Words:Transpose form FIR filter, multiple constant multiplications (MCM) technique, Block processing
Several designs have been designed by various researchers for efficient realization of FIR filters (having Fixed coefficients) using multiple constant multiplication (MCM) and distributed arithmetic(DA) [6] and methods [7]. DA-based designs use lookup tables (LUTs) to store pre-computed result stored the computational complexity.
1. INTRODUCTION Finite Impulse response (FIR) digital filter is used in several DSP applications, such as, echo cancellation, speech processing, equalization, adaptive noise cancellation, and various communication applications, including software-defined radio (SDR), etc. Many of these applications require FIR filters of large order to meet the stringent frequency specifications. And this filters need to support high sampling rate for high-speed digital communication. The number of multiplications and additions required for their filter output, increases linearly with the filter order.
The Transpose form FIR filter only needs N delay units, where N is the order of the filter – potentially half as much as direct form. This structure is obtained by reversing the order of the numerator and denominator sections of Direct Form, since they are in fact two linear systems. Then, one will notice that there are two columns of delays that tap off the center net, and these can be combined since they are redundant. The disadvantage is that Transpose form increases the possibility of arithmetic overflow for filters of high Q or resonance. This is because, conceptually, the signal is first passed through an all-pole filter (which normally boosts gain at the resonant frequencies) before the result of that is
There is no redundant computation available in the FIR filter, real-time implementation of a large order FIR filter in a resource constrained environment is a challenging task. Filter coefficients very often remain constant and known a priori in signal processing applications. This feature has been utilized to reduce the complexity of realization of multiplications. FIR filter has two
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