广义Chebyshev最优滤波器设计

本文论证了等波纹广义Chebyshev函数滤波器的最优化特性，提出了由设计指标得到广义Chebyshev函数的方法，并且引入信号流图非常简便的得到了对应网络的拓扑结构，最终完成滤波器的设计．本文对具有带外传输零点的滤波器设计具有相当重要的意义．     

广义Chebyshev滤波器传输零点的确定

传输零点的确定是交叉耦合滤波器综合的最基本要素.本文利用广义Chebyshev函数的极值特性以及滤波器阶数与传输零点最大值的关系,提出了一种根据滤波器特性指标同时确定广义Chebyshev滤波器的阶数和传输零点位置的方法,弥补了传统方法中传输零点确定的人为随意性,在满足技术指标条件下,实现了广义Chebyshev滤波器阶数最少,传输零点位置最佳.几个数值实验显示了该方法的过程和有效性.     

带不等式约束的线性相位FIR数字滤波器的Chebyshev设计

本文主要讨论带不等式约束的线性相位FIR数字滤波器的Chebyshev设计问题.我们知道,交错点组定理是Remez算法的理论基础,而此算法很好的解决了无约束线性相位FIR数字滤波器Chebyshev设计问题.本文中给出并证明了一个与交错点组定理类似的定理,并以此定理为依据设计算法求解具有不等式约束的线性相位FIR滤波器Chebyshev设计问题,此算法可通过对Matlab中remez()函数的修改来实现.     

基于Matlab的Chebyshev数字滤波器设计

文章分析了Chebyshev滤波器的特性，并用Matlab语言中的信号处理工具箱所提供的相关函数设计了Chebyshev数字低通滤波器，使Chebyshev滤波器的设计变得非常简单、直观。     

一种X波段同轴双工器设计

在具有有限传输零点的广义Chebyshev带通滤波器的综合理论基础上,根据计算出的耦合矩阵设计滤波器仿真模型,应用电磁仿真软件结合最优化方法,采用群时延拟合法对双工器的尺寸进行优化设计.实物测试结果表明,双工器的插入损耗≤1.5 dB,输入输出电压驻波比≤1.5,带外抑制大于85 dB,得到的实测曲线满足设计要求,论证了该方法的正确性.     

外辐射源雷达模糊函数副峰抑制算法研究

外辐射源雷达模糊函数副峰可能会导致检测虚警及弱小目标遮蔽.为抑制模糊函数副峰,提出了一种基于广义旁瓣对消结构的接收机滤波器设计方法,得到了广义旁瓣对消滤波器的闭式解,定量分析了该方法的信噪比损失,指出了副峰高度等因素与信噪比损失的关系.为避开滤波器设计中的高维矩阵求逆运算,提出了快速实现方法.理论分析及基于实测数据的数值计算结果表明,算法能将模糊函数副峰抑制到任意高度,且具有最小的信噪比损失.     

Chebyshev过渡型滤波器设计和分析

传统的Chebyshev滤波器具有较差的相位特性,其阶跃响应具有较大的过冲和较长的调节时间。本文从传递函数的极点角度,对Chebyshev滤波器进行了改进,改进后的滤波器表现出典型的过渡特性,在对幅度特性影响较小的情况下,改善了传统Chebyshev滤波器的相位特性和阶跃响应。通过对滤波器极点的调整,消除了传统Chebyshev滤波器过冲和传统偶数阶Chebyshev滤波器的稳态误差。     

4阶Chebyshev有源滤波器的设计与实现

提出了一种设计4阶Chebyshev有源滤波器的新方法。采用Pspice仿真软件对Chebyshev 4阶有源滤波器进行了仿真分析,结果表明该电路具有较高的稳定性。     

复FIR数字滤波器幅值约束Chebyshev设计

L.J.Karam和McClellan最早得到了有关复数域Chebyshev逼近的复交错点组定理,并提出了以此定理为基础的复Remez算法用于复FIR数字滤波器的Chebyshev设计.本文首先给出并证明了复交错点组定理在带不等式约束条件下的扩展定理,之后,根据此扩展定理中对最优解极值频率点特性的描述,提出了一种有效的算法来解决带幅值不等式约束的复FIR数字滤波器的Chebyshev设计问题.这一新算法中还结合了复Remez算法及赖晓平提出的迭代Remez算法,并且如果问题的解存在则保证收敛到此解.作者把上述算法做成了MATLAB语言程序,并进行了大量的实例设计实验,仿真结果表明此算法有效而可靠.     

带通与低通级联滤波器的设计

设计了一款应用于高铁系统上的双路同轴腔体滤波器,采用了带通与低通滤波器级联仿真方法,对其远端谐波进行有效抑制,从而提高滤波器带外的滤波性能。通过HFSS与Designer的联合仿真,用广义切比雪夫（General Chebyshev）滤波函数实现了中心频率为5 660 MHz,通带带宽为380 MHz,远端抑制达到25 dB的低插损高抑制的性能指标。最后对比了测试与仿真结果,得出带通滤波器级联低通滤波器可以实现带外高抑制的结论。     

Mathematical methods for the design of color scanning filters

The problem of the design of color scanning filters is addressed in this paper. The problem is posed within the framework of the vector space approach to color systems. The measure of the goodness of a set of color scanning filters presented in earlier work is used as an optimization criterion to design color scanning filters modeled in terms of known, smooth, nonnegative functions. The best filters are then trimmed using the gradient of the mean square DeltaE(ab) error to obtain filters with a lower value of perceptual error. The results obtained demonstrate the utility of the method.     

3型FIR高阶多通带滤波器的自适应优化设计研究

本文详细讨论了3型线性相位滤波器幅频特性与正弦基神经网络算法间的关系，提出了该算法的收敛定理，给山了有限脉冲响应（FIR）高阶多通带滤波器自适应优化设计算法及实例。计算机仿真结果表明了该算法在FIR高阶多通带滤波器的有效性和优异性能。     

Lowpass delay filters with flat magnitude and group delay constraints

This paper describes the design of finite impulse response (FIR) delay filters that minimize a squared error and have prescribed number of zeros at /spl omega/=/spl pi/ and prescribed magnitude and group delay flatness at /spl omega/=0. An important special case is the design of least squared error lowpass filters with prescribed flatness constraints and zeros at /spl omega/=/spl pi/. Even though the flatness constraints are in general nonlinear functions of the filter coefficients, we show the remarkable fact that for a subclass of the filters a simple orthogonal projection of least squared error filters onto a special linear subspace determined via Baher (1982) filters gives the solution. The paper also introduces the notion of delay filters that are high-order approximations to the ideal delay and establishes their equivalence to Baher filters. This connection gives novel elementary derivations of Baher filters and their properties. Matlab programs are provided at the end of the paper for the design of filters described in this paper.     

基于差分器的开关电流高通梯形滤波器的设计

本文应用一种新型的双线性/前馈差分器(BFD)来设计开关电流(SI)高通梯形滤波器。这种BFD是用本文提出的SI模块,通用差分器(GD)构成的,此GD具有多种差分功能。文中按S域频带变换和Z域带变换分别介绍了两种不同的设计方法,还给出了Chebyshev高通滤波器和椭圆(Elliptic)高通滤波器设计的实例。     

Implementation of Digital Unbiased FIR Filters with Polynomial Impulse Responses

This paper addresses the design and implementation of digital unbiased finite impulse response (FIR) filters with polynomial impulse response functions. The transfer function, its fundamental properties, and a general block-diagram are discussed for the impulse response represented with the l-degree Taylor series expansion. As a particular results, we show a fundamental identity uniquely featured to such filters in the transform domain. For low-degree impulse responses, the transfer functions are found in simple closed forms and represented in compact block-diagrams. The magnitude and phase responses are also analyzed along with the group delays. A comparison with predictive FIR filters is given. As examples of applications, filtering of time errors of local clocks is discussed along with the low-pass filter design employing a cascade of the unbiased FIR filters.     

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。     

A fast matrix iterative technique for the WLS design of 2-D quadrantally symmetic FIR filters

High computational complexity is a major problem encountered in the optimal design of two-dimensional (2-D) finite impulse response (FIR) filters. In this paper, we present an iterative matrix solution with very low complexity to the weighted least square (WLS) design of 2-D quadrantally symmetric FIR filters with two-valued weighting functions. Firstly, a necessary and sufficient condition for the WLS design of 2-D quadrantally symmetric filters with general nonnegative weighting functions is obtained. Then, based on this optimality condition, a novel iterative algorithm is derived for the WLS design problem with a two-valued weighting function. Because the filter parameters are arranged in their natural 2-D form and the transition band is not sampled, the computation amount of the proposed algorithm is reduced significantly, especially for high-order filters. The exponential convergence of the algorithm is established, and its computational complexity is estimated. Design examples demonstrating the convergence rate and solution accuracy of the algorithm, as well as the relation between the iteration number of the algorithm and the size and transition-band width of the filter are given.     

A Direct Synthesis Approach for Microwave Filters With a Complex Load and Its Application to Direct Diplexer Design

This paper presents a direct synthesis approach for general Chebyshev filters terminated with a complex load. The new approach is based on the fact that the polynomial functions for synthesizing the filters are composed for any matched loads. By normalizing the polynomial functions with assumed complex matched load impedance by a real reference load impedance using power waves normalization, a set of new polynomial functions for the same filter, but with real load impedance, can be formulated, from which the coupling matrix for the physical filter design can be obtained using a standard direct filter synthesis approach. This new direct synthesis approach can find many applications. A practical application is the direct diplexer design with a realistic junction model being taken into account. With the diplexer design is concerned, a fast-converged iterative scheme is proposed. The effectiveness and the validation of the proposed scheme are demonstrated by two design examples     

Gabor expansion for adaptive echo cancellation

A good echo cancellation algorithm should have a fast convergence rate, small steady-state residual echo, and less implementation cost. The normalized least mean square (NLMS) adaptive filtering algorithm may not achieve this goal. We show that using the Gabor expansion is a way to achieve this goal. For direct digital signal processing compatibility the Gabor expansion introduced in this paper is for discrete-time signals, although the Gabor expansion also can be used for continuous-time signals. The Gabor expansion can be defined as a discrete-time signal representation in the joint time-frequency domain of a weighted sum of the collection of functions (known as the synthesis functions). There are several design issues in the echo canceller based on the Gabor expansion: the design of the analysis functions for the far-end speech, the design of the analysis functions for the near-end signal containing the echo plus the near-end speech, the design of the adaptive filters in the subsignal path, and the design of the synthesis functions. All the adaptive filters are designed using identical NLMS adaptive filtering algorithms     

基于Serenade仿真软件的微波电路优化设计

介绍了微波电路与Serenade系统仿真软件的功能,并以对微波低通滤波器的仿真设计为例说明了对它们的应用.同时以巴特沃斯原型滤波器为基础,分析了该滤波器的特性,并对通过优化得到满足设计目标的低通滤波器进行了介绍.