具有近似线性相位特性的多相波数字滤波器的设计

不考虑相位失真,而要求满足比较苛刻的振幅特性的时候,和FIR滤波器比较起来,采用 IIR 滤波器,计算量要小很多.但对某些IIR滤波器,采取适当的方法,也可以使其相位失真变得很小.本文提出一种新的设计方法,用来设计振幅响应完全满足设计要求,而相位特性用Chebyshev 近似来实现的多相波数字滤波器.这种方法的关键在于确定通带中的若干衰减零点.文中对需要的最小衰减零点数作了估计.实例表明,用这种方法设计的滤波器,时延小,相位特性非常接近线性.     

Least-squares design of IIR filters with prescribed magnitude andphase responses and a pole radius constraint

This paper presents a method for the frequency domain design of infinite impulse response (IIR) digital filters. The proposed method designs filters approximating prescribed magnitude and phase responses. IIR filters of this kind can have approximately linear-phase responses in their passbands, or they can equalize magnitude and phase responses of given systems. In many cases, these filters can be implemented with less memory and with fewer computations per output sample than equivalent finite impulse response (FIR) digital filters. An important feature of the proposed method is the possibility to specify a maximum radius for the poles of the designed rational transfer function. Consequently, stability can be guaranteed, and undesired effects of implementations using fixed-point arithmetic can be alleviated by restricting the poles to keep a prescribed distance from the unit circle. This is achieved by applying Rouche's theorem in the proposed design algorithm. We motivate the use of IIR filters with an unequal number of poles and zeros outside the origin of the complex plane. In order to satisfy simultaneous specifications on magnitude and phase responses, it is advantageous to use IIR filters with only a few poles outside the origin of the z-plane and an arbitrary number of zeros. Filters of this type are a compromise between IIR filters with optimum magnitude responses and phase-approximating FIR filters. We use design examples to compare filters designed by the proposed method to those obtained by other methods. In addition, we compare the proposed general IIR filters with other popular more specialized structures such as FIR filters and cascaded systems consisting of frequency-selective IIR filters and phase-equalizing allpass filters     

Generalized digital Butterworth filter design

This correspondence introduces a new class of infinite impulse response (IIR) digital filters that unifies the classical digital Butterworth filter and the well-known maximally flat FIR filter. New closed-form expressions are provided, and a straightforward design technique is described. The new IIR digital filters have more zeros than poles (away from the origin), and their (monotonic) square magnitude frequency responses are maximally flat at ω=0 and at ω=π. Another result of the correspondence is that for a specified cutoff frequency and a specified number of zeros, there is only one valid way in which to split the zeros between z=-1 and the passband. This technique also permits continuous variation of the cutoff frequency. IIR filters having more zeros than poles are of interest because often, to obtain a good tradeoff between performance and implementation complexity, just a few poles are best     

巴特沃斯数字陷波滤波器的设计

随着数字技术的发展,数字滤波器在许多领域得到广泛的应用。研究一种在Matlab语言环境下设计IIR数字陷波滤波器的方法,在数字陷波滤波器设计过程中,先进行模拟低通滤波器的设计,然后进行模拟低通/模拟带阻滤波器转换,最后采用双线性变化法将模拟陷波滤波器转化成数字陷波滤波器。提出一种用所有零点和极点来表达数字陷波器传递函数的方法,同时给出以巴特沃斯模拟低通为原型设计数字陷波滤波器的程序。     

基于FIR与相位补偿IIR滤波器的雷达回波信号处理

FIR与IIR频率选择滤波器的设计,被广泛应用于数字信号处理领域之中。文章以雷达回波信号的数字处理为例,首先分别设计FIR,IIR滤波器完成了对信号特定频率分量的滤除。进而,针对IIR滤波器的非线性相位,基于最优化设计全通系统实现了相位补偿,并对FIR,IIR滤波器进行了综合比较。     

基于免疫算法的IIR数字滤波器优化与实现

由于IIR数字滤波器设计实质上是一个非线性高维复杂函数优化问题,文中提出基于具有全局搜索能力强,收敛速度快特点的免疫算法实现IIR数字滤波器优化设计的新方法,给出了IIR滤波器优化设计的数学模型,描述了应用免疫算法优化设计IIR数字滤波器的具体实现步骤。通过低通和高通IIR数字滤波器设计的仿真结果表明方法的有效性和高效性。     

数字滤波器设计中采样频率的作用和影响

在“数字信号处理”课程的学习和教学中,数字滤波器设计中采样频率的作用是一个较难理解和容易混淆的概念,本文详细讨论了采和频率在数字滤波器设计中的作用和影响,从数学原理和物理概念两方面说明了采样频率的作用以及产生概念错误的原因。     

一种设计IIR数字滤波器的参数化方法

 基于连续时间状态空间结构和广义双线性变换,提出了一种设计无限冲激响应(IIR)数字滤波器的参数化方法.优点是稳定区域包含了整个参数空间,因此可以采用无约束优化方法.给出了仿真实例,并与已有的设计方法进行了比较,其通带波动、阻带衰减、群迟延等性能更为优越.     

一种有效的IIR数字滤波器优化设计方法

针对IIR数字滤波器优化设计实质上是一个多参数多目标优化问题,本文提出一种基于量子遗传算法的IIR数字滤波器满意优化设计方法,通过设计满意度函数而构造出满意优化计算模型,将滤波器性能指标的满意设计与参数优化统一考虑,并用本文提出的收敛速度快和全局寻优能力强的新量子遗传算法(NQGA)搜索满意解。通过低通和带通IIR数字滤波器的设计结果表明,该方法是有效、实用的。     

基于MATLAB的IIR数字滤波器设计研究

IIR数字滤波器属于经典数字滤波器的一种，详细描述了利用功能强大的MATLAB编程语言设计IIR数字滤波器的方法和步骤。     

A new approach to the design of complex all-pass IIR digital filters

A new method is proposed for designing complex all-pass IIR filters, the all-pass IIR filters with complex coefficients, in this paper. By minimizing the integration of certain square phase error over interested frequencies, an eigenvector of an appropriate real, symmetric and positive-definite matrix is computed to get the filter coefficients. The stability is achieved by specifying properly the desired phase specifications. If an appropriate iterative process is used, equiripple complex all-pass filter design can be obtained. The method is simple and the performance is comparable to the existing methods. Several examples are presented to demonstrate the effectiveness of the approach.     

IIR数字滤波器仿真实现

数字滤波技术是数字信号处理的一个重要组成部分,滤波器的设计是信号处理的核心问题之一。本文分析了在MATLAB环境下无限脉冲响应（IIR）数字滤波器设计的设计方法及仿真实现。     

IIR数字滤波器的Matlab和FPGA实现

提出一种通过两个二阶节级联构成四阶IIR数字椭圆滤波器的设计方法,并利用Matlab仿真软件设计了通带内波纹不大于0.1 dB,阻带衰减不小于42 dB的IIR数字滤波器。论述了一种采用可编程逻辑器件,通过VHDL硬件描述语言实现该滤波器的方法。给出了在QuartusⅡ软件下的仿真结果,并在FPGA器件上验证实现。实验证明,这种方法是切实可行的。     

Design of two-channel linear-phase QMF banks based on real IIR all-pass filters

The design of two-channel linear-phase quadrature mirror filter (QMF) banks constructed by real infinite impulse response (IIR) digital all-pass filters is considered. The design problem is appropriately formulated to result in a simple optimisation problem. Using a variant of Karmarkar's algorithm, the optimisation problem can be efficiently solved through a frequency sampling and iterative approximation method to find the real coefficients for the IIR digital all-pass filters. The resulting two-channel QMF banks possess an approximately linear phase response without magnitude distortion. The effectiveness of the proposed technique is achieved by forming an appropriate Chebyshev approximation of the desired phase response and then finding its solution from a linear subspace in a few iterations. Finally, several simulation examples are presented for illustration and comparison     

基于Matlab的IIR数字滤波器快速设计

针对数字滤波器的概念比较抽象,且数值计算较为繁琐的问题,文中给出了借助模拟滤波器快速设计IIR数字滤波器的方法,并在Matlab环境下做出了IIR滤波器的快速设计系统。设计实例及运行结果表明,该设计方法简化了IIR数字滤波器的设计程序,并大幅提高了设计效率。     

具有任意幅度频响的二维线性相位FIR数字滤波器的设计

本文提出了设计任意幅度频响的二维线性相位ＦＩＲ数字滤波器的解析最小二乘方法，通过最小化频域平方误差函数得到了滤波器系数的闭式解，运用导出的闭式式，可根据给定的任意幅度频响指标直接计算滤波器的系数，从而简化了滤波器设计程序，并大大降低了运算量。     

Realization of 2-D Variable IIR Digital Filter Structures with a Small Amount of Calculations for Coefficient Update

This paper proposes 2-D variable IIR digital filter structures with a small amount of calculations for coefficient update. The proposed realization method uses the 2-D parallel allpass structure derived from the separable denominator 2-D filter as the prototype structure for 2-D variable digital filters. In order to reduce the amount of calculations, all the redundant first-order complex allpass sections are combined by modularization of the variable structure. Furthermore, we can realize a very compact variable structure with a minimal number of first-order complex allpass sections by combining complex allpass sections with their complex conjugate allpass sections. Comparison of the calculation loads of the variable structures is presented to demonstrate that the amount of calculations for coefficient update of the proposed variable structure is far less than that of the original and the modular variable structure.     

数字滤波器在语音信号处理中的应用

针对语音信号去噪的问题,设计了各种类型的IIR数字滤波器,然后用不同类型的滤波器处理不同的噪声,这改变了传统的一成不变的去噪方式.实验结果表明,同样的噪声用不同的滤波器处理,效果各有不同,经过分析,选出最优的滤波方式.     

设计IIR数字滤波器的遗传优化算法

提出了ＩＩＲ数字滤波器设计的遗传优化法。这是一种模拟自然遗传和达尔文进化理论的随机并行优化算法。首先，详细描述了遗传算法并给出了计算步骤，然后将遗传算法用于ＩＩＲ数字滤波器的优化设计，最后给出了模拟计算结果。     

基于人工鱼群算法的IIR数字滤波器设计

将人工鱼群算法（AFSA）用于IIR数字滤波器设计，建立了相应的优化模型，给出了简化的人工鱼群算法及其实现步骤。最后，将该算法用于低通、带通IIR数字滤波器的设计，并与粒子群算法进行了比较。仿真结果证明了AFSA的有效性，并且具有算法灵活、简单，全局收敛性好。收敛速度快的优点。