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。     

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。     

基于差分进化算法和遗传算法的混合优化 算法及其在阵列天线方向图综合中的应用

阵列天线方向图综合作为智能天线的一项重要技术对于复杂系统的优化问题提出了更高的要求.本文结合差分进化的基本思想和遗传算法的基因交叉和变异方法构建了一种新的混合优化方法.该算法使用差分进化算子作为主要优化手段,结合遗传算法优胜劣汰的基本思想以及其中的交叉和变异方法,通过融合两种优化方法各自的优点,可以显著改善多参数、高度非线性问题的优化结果、提高计算效率.计算机仿真结果表明,与现有算法相比,该算法用于天线方向图综合具有收敛速度快、优化能力强、算法可靠等优势.     

进化规划用于自适应IIR滤波器的优化设计

针对自适应ＩＲ滤波器（ＡＩＲＦ）潜在的不稳定性和性能指标函数容易陷入局部极小点而导致性能下降等问题，本文将进化规划用于直接、并联、级联和格型结构的ＡＩＩＲＦ的优化设计。基于进化规划的自适应滤波算法不依赖于梯度信息，能够有效地实现ＡＩＩＲＦ参数的全局寻优。大量的仿真实验结果表明不同结构的ＡＩＲＦ用进化规划进行参数寻优，不仅解决了自适应滤波器性能指标函数容易陷入局部极小点的问题，亦解决了ＡＩＲＦ的稳定性问题。     

纯相位二值化匹配滤波器的优化设计

通过采用神经网络中的Clipping方法和MonteCarlo修改学习算法,对用于光学模式识别的纯相位二值化匹配滤波器进行了优化设计。计算机模拟结果表明,和传统的纯相位匹配滤波器的相关输出结果相比,其识别输出的信噪比和信号相关峰值得到了明显的提高,从而为今后的光学实现奠定了良好的基础。     

声表面波滤波器的匹配电路设计

介绍了通过测试仪器采集的声表面波（SAW）滤波器的Sij(i,j=1,2）参数来优化匹配电路的方法。首先将采集的Sij(i,j=1,2）参数转换为SAW滤波器Yij(i,j=1,2）参数，然后建立新的S12（或S21）参数与匹配电路的依赖关系，通过优化匹配电路元件值，而使滤波器的插入损耗和通带波动满足目标值，该方法的主要优点是考虑整个通带特性，而不是考虑通带内的某一点（如中心频率）。     

一种扬声器频响的自适应数字滤波优化补偿方法

从模拟滤波器到数字滤波器的转换以及寻找滤波器参数的最优解是IIR参数滤波器用于扬声器频响实时补偿的两个关键问题。本文提出一种根据模拟滤波器的中心频率、增益和品质因数来自适应选择S域到Z域转换方法,通过扬声器频响曲线的实时包络来划分峰谷,给出了一种滤波器参数的优化方法,提升了数字滤波器与模拟原型的匹配度,从而减少滤波器个数、加速了滤波器的优化计算。实验结果表明,所提出的方法使补偿滤波器的个数和总时间开销比现有的补偿方法分别减少了大约43%和55%。     

一种新的基于极大似然估计的系统辨识方法

进化计算是一种基于自然选择和自然变异机制的并行随机优化算法。由于递推极大似然估计法难以实现性能指标函数的全局寻优，所以本文提出了将改进的进化计算用于系统参数辨识的方法。计算机仿真结果表明，该算法能够实现似然函数的全局寻优。     

自适应小波的构造及其在信号处理中的应用

基于带限正交小波基的特性,本文采用匹配方法构造了一种新的带限尺度函数,它与信号的主要能量所在频带具有相似的特征.匹配尺度滤波器是优化滤波器,它锁定能量聚集的频带,使得所需频率分量的输出增大.原始信号能够用优化的小波实时处理.通过对脑电图信号的处理,证明本文算法是有效的.     

准椭圆函数滤波器原型电路参数的优化提取

准椭圆函数滤波器是一种新型的高性能滤波器形式 ,但是由于其原型电路的形式比较复杂 ,用经典综合的方法提取其参数的效率很低 ,限制了这种形式滤波器的应用。本文结合遗传算法和Solvopt算法 ,提出了一种新的有效而灵活的准椭圆函数滤波器原型电路参数的优化提取方法     

图像滤波的形态学开、闭型神经网络算法

该文设计完成了一种具有实用意义的形态学开、闭滤波的神经网络模型及其滤波参数的优化训练算法。实验结果表明该方法设计简便,实用性强且易于推广,对提高形态滤波性能效果明显。分析表明,形态滤波器可分解为形态滤波运算和结构元素选择两个基本问题。形态滤波运算规则已由定义本身确定,于是形态滤波器的最终滤波性能就仅仅取决于结构元素的选择。进行自适应优化训练的目的正是使结构元素具有图像目标的形态结构特征,从而使形态滤波器对复杂变化的图像具有良好的滤波性能和稳健的适应能力。     

Variable digital filter design using the outer product expansion

Digital filters with adjustable frequency domain characteristics are referred to as variable digital filters. Variable filters are useful in the applications where the filter characteristics are required to be changeable during the course of signal processing. Especially in real time applications, variable filters are needed to change their coefficients instantaneously such that the real time signal processing can be performed. The present paper proposes a very efficient technique for variable 1D digital filter design. Generally speaking, the variable coefficients of variable digital filters are multidimensional functions of a set of spectral parameters which define the desired frequency domain characteristics. The authors first sample the given variable 1D magnitude specification and use the samples to construct a multidimensional array, then propose an outer product expansion method for expanding the multidimensional array as the sum of outer products of 1D arrays (vectors). Based on the outer product expansion, one can reduce the difficult problem of designing a variable 1D digital filter to the easy one that only needs constant 1D filter designs and 1D polynomial approximations. The technique can obtain variable 1D filters having arbitrary desired magnitude characteristics with a high design accuracy     

Precise Design of Coaxial Low-Pass Filters

The coaxial low-pass filters described are of the conventional stepped impedance type consisting of a cascade of alternating low and high impedance sections of line. Exact prototype filters having Chebyshev equal-ripple characteristics are obtained from published tables giving the characteristic impedances of the sections. The capacitive discontinuities at the junctions are compensated by a new method which is exact at the cutoff frequency, and nearly exact in the region of this frequency. The production of low-pass filters with a passband VSWR of 1.05 or less is feasible and experimental results are described for such designs.     

Planar three-resonator bandpass filters with cross coupling

New designs of planar three-resonator bandpass filters with cross coupling having a large variety of frequency characteristics are considered. In addition to better one-sided selectivity, such filters implement symmetric amplitude–frequency characteristics with an attenuation pole at each side of the passband. These filters can also have constant delay time in the passband. Concatenation of the proposed three-resonator filters leads to multiresonator filters with high selectivity determined by two attenuation poles at each side of the passband. It is found that the type of connection of the middle resonator in the circuit of a three-resonator filter with cross coupling results in substantial differences in amplitude–frequency characteristics. The results of modeling of different frequency characteristics are presented. It is shown that filters have small dimensions, which are comparable to overall dimensions of microwave ceramic filters. For example, dimensions of a three-resonator stripline filter designed for a frequency of 1.9 GHz are 9.4 × 5 × 2 mm for the permittivity of the filter material ε_r = 92 and dimensions of a six-resonator filter are 10 × 9.4 × 2 mm.     

An approximation technique for the design of recursive digital and continuous filters with and without fixed zeros in the stop band

The bilinear z-transformation has been used by various authors (Golden and Kaiser 1964, Broomer 1966) to design recursive digital filters. The necessity to select an equivalent. continuous filter makes this method very laborious. Remes exchange algorithm has also been used in the design of recursive filters (Remes 1957, Deczky 1974) but not will the same success as for the design of non-recursive filters (McClennan and Parks 1973. Holt et al. 1975 ) due to its dependence on the initial conditions on optimization methods. In this paper we-present a design technique, based on Remes second exchange algorithm. This provides a versatile approximation method for the design of a wide range of minimax-type digital recursive filters. Furthermore, the method is extended to the design of continuous filters using suitable mapping methods. In the examples given, filters arc designed with various frequency characteristics for the pass band and the stop band and also with predefined zeros in the stop band.     

Direct-Coupled Cavity Filters for Wide and Narrow Bandwidths

Direct-coupled resonator filters in transmission line are discussed. The resonators consist of sections of transmission line coupled either by series capacitances or shunt inductances. Over narrow frequency bands, such filters show characteristics similar to those of lumped-constant filters and their design is straightforward. The design of direct-coupled resonator filters over wide (as well as narrow) frequency bands is presented here using the quarter-wave transformer as a prototype circuit. Several numerical examples (with fractional bandwidths between 10 per cent and 85 per cent) are worked out to illustrate the method. It is shown that the response can be improved by optimizing the line impedances.     

Design and Implementation of Linear Phase FIR Filters for Biological Signal Processing

This paper presents a new method for designing digital linear phase, finite impulse response filters with loose frequency response characteristics, but with good time resolution as is required in biological signal conditioning. The design is very simple and has been used with success in the microcomputer implementation of filters for the automated processing of electroencephalographic (EEG) data. Examples and a discussion of possible filter implementations are included.     

基于双正交小波的光阑小波滤波器

提出了一种应用于4f光学系统的光学小波滤波器的设计与制作方法.结合光学信号的优势与小波变换的优点,利用双正交小波的共轭镜像特性构造出了频域形式的分解和重构滤波器.通过将滤波器放置在4f系统的频谱面上对图像成功实现了二维分解和重构.另外还根据信息处理要求和采样器件的特性,制作了振幅型和位相型两种小波滤波器.这两套滤波器都...     

Design of nonseparable 3-D filter banks/wavelet bases usingtransformations of variables

The authors present a technique to design two-channel filter banks in three dimensions where the sampling is on the FCO (face centred orthorhombic) lattice, The ideal 3-D sub-band is of the truncated octahedron shape. The design technique is based transformation of variable method equivalent to the generalised McClellan transformation. The filters are FIR, have linear phase and achieve perfect reconstruction. Although the sub-band shape is quite complicated, the ideal frequency characteristics are well approximated. This is illustrated with an example. The technique provides the flexibility of controlling the frequency characteristics of the filters with ease. The filters can be implemented quite efficiently due to the highly symmetrical nature of the coefficients of the transformation. The authors also modify and extend the basic design technique to impose the zero property (the number of zeros of the filter transfer function at the aliasing frequency) on the sub-band filters. This property is important when the filter bank is used iteratively in a tree-structured manner as a discrete wavelet transform system and the issue of regularity arises. Several design examples are presented to illustrate the design technique