Multirate Techniques in Filter Design and Implementation

2009 ◽  
pp. 274-294
Author(s):  
Ljiljana Milic
Keyword(s):  
Digital Filters ◽  
Filter Design ◽  
Fir Filter ◽  
Single Stage ◽  
Sharp Transition ◽  
Filter Length ◽  
Iir Filters ◽  
Iir Filter ◽  
Design And Implementation ◽  
Promising Solution

Digital filters with sharp transition bands are difficult, sometimes impossible, to be implemented using single-stage structures. A serious problem with a single-stage sharp FIR filter is its complexity. The FIR filter length is inversely proportional to the transition–width and complexity becomes prohibitively high for sharp filters, (Lim, 1986). IIR filters with sharp transition bands suffer from extremely high sensitivities of transfer function poles. In many practical cases, the multirate approach is the promising solution that could be applied for implementation of a sharp FIR or IIR filter. In this chapter, we present two methods for designing filters having narrow transition bandwidths: multistage filtering suitable for narrowband filters, and the method based on multirate and complementary filtering, which may be used for filters of arbitrary bandwidths.

Low computation digital down converter using polyphase IIR filter

Circuit World ◽  
2019 ◽  
Vol 45 (3) ◽  
pp. 169-178 ◽  
Author(s):  
Hiren K. Mewada ◽  
Jitendra Chaudhari
Keyword(s):  
Group Delay ◽  
Filter Design ◽  
Fir Filter ◽  
Linear Phase ◽  
Content Type ◽  
Iir Filters ◽  
Iir Filter ◽  
Alternative Option ◽  
Digital Down Converter ◽  
Sample Rate

Purpose The digital down converter (DDC) is a principal component in modern communication systems. The DDC process traditionally entails quadrature down conversion, bandwidth reducing filters and commensurate sample rate reduction. To avoid group delay, distortion linear phase FIR filters are used in the DDC. The filter performance specifications related to deep stopband attenuation, small in-band ripple and narrow transition bandwidth lead to filters with a large number of coefficients. To reduce the computational workload of the filtering process, filtering is often performed as a two-stage process, the first stage being a down sampling Hoegenauer (or cascade-integrated comb) filter and a reduced sample rate FIR filter. An alternative option is an M-Path polyphase partition of a band cantered FIR filter. Even though IIR filters offer reduced workload to implement a specific filtering task, the authors avoid using them because of their poor group delay characteristics. This paper aims to propose the design of M-path, approximately linear phase IIR filters as an alternative option to the M-path FIR filter. Design/methodology/approach Two filter designs are presented in the paper. The first approach uses linear phase IIR low pass structure to reduce the filter’s coefficient. Whereas the second approach uses multipath polyphase structure to design approximately linear phase IIR filter in DDC. Findings The authors have compared the performance and workload of the proposed polyphase structured IIR filters with state-of-the-art filter design used in DDC. The proposed design is seen to satisfy tight design specification with a significant reduction in arithmetic operations and required power consumption. Originality/value The proposed design is an alternate solution to the M-path polyphase FIR filter offering very less number of coefficients in the filter design. Proposed DDC using polyphase structured IIR filter satisfies the requirement of linear phase with the least number of computation cost in comparison with other DDC structure.

Optimized DA-reconfigurable FIR filters for software defined radio channelizer applications

Circuit World ◽  
2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
C. Srinivasa Murthy ◽  
K. Sridevi
Keyword(s):  
Energy Efficiency ◽  
Power Dissipation ◽  
Software Defined Radio ◽  
Filter Design ◽  
Finite Impulse Response ◽  
Software Tool ◽  
Building Blocks ◽  
Fir Filter ◽  
Content Type ◽  
Filter Length

Purpose In this paper, the authors present different methods for reconfigurable finite impulse response (RFIR) filter design. Distributed arithmetic (DA)-based reconfigurable FIR filter design is suitable for software-defined radio (SDR) applications. The main contribution of reconfiguration is reuse of registers, multipliers, adders and to optimize various parameters such as area, power dissipation, speed, throughput, latency and hardware utilizations of flip-flops and slices. Therefore, effective design of building blocks will be optimized for RFIR filter with all the above parameters. Design/methodology/approach The modified, direct form register structure of FIR filter contributes the reuse concept and allows utilization of less number of registers and parallel computation operations. The disadvantage of DA and other conventional methods is delay increases proportionally with filter length. This is due to different partial products generated by adders. The usage of adder and multipliers in DA-FIR filter restricts the area and power dissipation because of their complexity of generation of sum and carry bits. The hardware implementation time of an adder can be reduced by parallel prefix adder (PPA) usage based on Ling equation. PPA uses shift-add multiplication, which is a repetitive process of addition, and this process is known as Bypass Zero feed multiplicand in direct multiplication, and the proposed technique optimizes area-power product efficiently. The modified DA (MDA)-based RFIR filter is designed for 64 taps filter length (N). The design is developed by using Verilog hardware description language and implemented on field-programmable gate array. Also, this design validates SDR channel equalizer. Findings Both RFIR and SDR are integrated as single system and implemented on Artix-7 development board of XC7A100tCSG324 and exploited the advantages in area-delay, power-speed products and energy efficiency. The theoretical and practical comparisons have been carried out, and the results are compared with existing DA-RFIR designs in terms of throughput, latency, area-delay, power-speed products and energy efficiency, which are improved by 14.5%, 23%, 6.5%, 34.2% and 21%, respectively. Originality/value The DA-based RFIR filter is validated using Chipscope Pro software tool on Artix-7 FPGA in Xilinx ISE design suite and compared constraint parameters with existing state-of-art results. It is also tested the filtering operation by applying the RFIR filter on Audio signals for removal of noisy signals and it is found that 95% of noise signals are filtered effectively.

Efficient Multirate Filtering

2002 ◽  
pp. 105-142 ◽  
Author(s):  
Ljiljana D. Milic ◽  
Miroslav D. Lutovac
Keyword(s):  
Digital Filter ◽  
Filter Design ◽  
Narrow Band ◽  
Sampling Rate ◽  
Wide Band ◽  
Digital Filter Design ◽  
Iir Filter ◽  
Design And Implementation ◽  
Sampling Rate Conversion ◽  
Rate Conversion

Application of multirate techniques to improve digital filter design and implementation are considered in this chapter. FIR and IIR filter design and implementation for sampling rate conversion by integer and rational factors are presented. Sharp narrow-band and wide-band multirate design techniques are discussed. Accurate designs of FIR and IIR half-band filters are described in detail. Several examples are provided to illustrate the multirate approach to filter design.

scholarly journals Comparison of Circular Symmetric Low-Pass Digital IIR Filter Design Using Evolutionary Computation Techniques

Mathematics ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 1226 ◽  
Author(s):  
Omar Avalos ◽  
Erik Cuevas ◽  
Jorge Gálvez ◽  
Essam H. Houssein ◽  
Kashif Hussain
Keyword(s):  
Evolutionary Computation ◽  
Transfer Functions ◽  
Filter Design ◽  
Statistical Treatment ◽  
Optimization Methods ◽  
Intelligence Community ◽  
Infinite Impulse Response ◽  
Iir Filters ◽  
Iir Filter ◽  
Wide Range

The design of two-dimensional Infinite Impulse Response (2D-IIR) filters has recently attracted attention in several areas of engineering because of their wide range of applications. Synthesizing a user-defined filter in a 2D-IIR structure can be interpreted as an optimization problem. However, since 2D-IIR filters can easily produce unstable transfer functions, they tend to compose multimodal error surfaces, which are computationally difficult to optimize. On the other hand, Evolutionary Computation (EC) algorithms are well-known global optimization methods with the capacity to explore complex search spaces for a suitable solution. Every EC technique holds distinctive attributes to properly satisfy particular requirements of specific problems. Hence, a particular EC algorithm is not able to solve all problems adequately. To determine the advantages and flaws of EC techniques, their correct evaluation is a critical task in the computational intelligence community. Furthermore, EC algorithms are stochastic processes with random operations. Under such conditions, for obtaining significant conclusions, appropriate statistical methods must be considered. Although several comparisons among EC methods have been reported in the literature, their conclusions are based on a set of synthetic functions, without considering the context of the problem or appropriate statistical treatment. This paper presents a comparative study of various EC techniques currently in use employed for designing 2D-IIR digital filters. The results of several experiments are presented and statistically analyzed.

A second order s-to-z transform and its implementation to IIR filter design

2014 ◽  
Vol 33 (5) ◽  
pp. 1831-1843 ◽  
Author(s):  
Dejan Mirković ◽  
Predrag Petković ◽  
Vančo Litovski
Keyword(s):  
Digital Filters ◽  
Group Delay ◽  
Transfer Functions ◽  
Filter Design ◽  
Second Order ◽  
Pass Band ◽  
Content Type ◽  
Iir Filter ◽  
Band Group ◽  
Iir Digital Filters

Purpose – The purpose of this paper is to design a tool for IIR digital filters obtained from analog prototypes, which preserves simultaneously the amplitude and the group delay response. Design/methodology/approach – A new s-to-z transform is developed based on a second order formula used for numerical integration of differential equations. Stability of the newly obtained transfer functions in the z-domain is proved to be preserved. Distortions introduced by the new transform into the original amplitude and group delay responses are studied. Findings – The new formula, when implemented to all-pole prototypes, exhibits lower selectivity than the original while reducing the pass-band group delay distortions. In the same time its structure is importantly simpler than the functions obtained by the well-known bilinear transform. When implemented to a prototype having “all kinds” of transmission zeros the resulting filter has almost ideally the same characteristic as the prototype. Research limitations/implications – The new transform may be used exclusively to synthesize even order filters. The new function is twice the order of the analog prototype. This kind of transformations are used to design IIR digital filters only. Low-pass transfer functions were studied being prototypes for all other cases. Originality/value – This is a new result never mentioned in the literature. Its effectiveness is confined to a niche problem when simultaneous sharp selectivity and low group delay distortions are sought.

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