用窗函数设计FIR数字滤波器

FIR滤波器克服了IIR滤波器的缺点,使滤波器更稳定,同时也有了严格的线性相位特性。用FIR设计滤波器是选择有限长度的h（n）,是传输函数H（e^jw）满足技术要求。其中窗函数法是一种重要的FIR滤波器的设计方法,用MATLAB编写程序设计FIR数字滤波器。     

舰船宽带连续谱噪声的模拟

首先对舰船辐射噪声信号的时域特性和频域特性进行了分析讨论,根据噪声的连续谱特性,提出了一种用FIR滤波器实现宽带噪声信号模拟的方法。由于舰船宽带信号的连续谱在高频段具有-6dB/oct的衰减特性,因此该FIR滤波器的幅频响应也要与此一致,且为线性相位,即该滤波器的频率响应要具有特定的形状。采用了自适应方法很方便地实现了该特定频率响应FIR滤波器的设计,再将高斯白噪声信号通过该滤波器即实现宽带噪声信号的模拟。仿真结果表明,该方法较真实地模拟出任意给定频域特征的宽带连续谱噪声信号。     

一种新型高速FIR滤波器构造方法

针对传统串行滤波器无法满足工程实时性要求的问题,在分析传统FIR滤波器处理结构的基础上,提出一种基于多滤波器并行处理方式的高速FIR滤波器设计方法,使用多个低速率低阶数滤波器并行工作达到高速率高阶数滤波器的处理效果。仿真试验表明:该方法能够基于FPGA并行处理的架构,实现高速FIR滤波器的有效设计,解决在工程应用中高速率滤波器设计困难的问题。     

双光纤方向耦合器组成的梳状滤波器

提出了一种由双光纤定向耦合器组成的光学梳状滤波器,由传输矩阵法推导出了该模型输出光谱与有关参数之间关系的数学表达式,对决定滤波器输出光谱特性及其规律的相关参数进行了详细讨论。模拟与分析表明,在一定条件下,输出光谱半宽度?λ1/2、输出消光比以及波长隔离度等仅与耦合器的耦合比系数有关,具有明显的法布里-珀罗腔多光束干涉的特点,耦合比系数非常类似法布里-珀罗腔中的反射率,通过控制耦合比系数可以调节滤波器的输出光谱半宽度?λ1/2、输出消光比、波长隔离度,已适用不同的应用要求。     

基于一种新的三模集的低通FIR数字滤波器设计

本文对低通有限脉冲响应(FIR)数字滤波器的设计进行了研究;在对常用三模集和传统的具有脉冲响应系数的FIR数字滤波器分析的基础上,提出将一种新的三模集应用于低通FIR数字滤波器设计的新方法。该FIR滤波器由多个乘法-累加器单元构成,实现正向转换器、并行算术通道和逆向转换器的功能。正向转换器将一个二进制数编码成一个关于模集的余数表示的数,每个算术通道对模集的每个模进行模乘和累加,逆向转换器将一个余数表示的数解码为其等效的二进制数,算术通道以完全并行的架构工作,从而实现轻量化的计算和简单的结构;最后的仿真实验结果不仅验证了本文提出的设计方法的有效性,而且相比于传统的单向转换设计,本文提出的设计方法有更小的滤波器系数偏差和更好的频率响应等波纹特性。     

基于余弦基神经网络的FIR滤波器设计

提出了一种基于余弦基神经网络FIR滤波器的设计方法。根据线性相位FIR滤波器的幅频特性是有限项的傅里叶级数,构造了一个三层余弦基神经网络模型,并给出了最优隐层神经元的个数。经模拟仿真,滤波器性能非常理想,具有同时输出低通、高通、带通、带阻各种功能,通带、阻带无过冲无波动,边界频率可以精确控制。     

表面测量中抗混叠数字滤波器的设计与实现

在表面测量数据采集系统中,针对抗混叠滤波器设计问题,提出了“模拟滤波器＋数字滤波器”的设计方法．设计了具有线性相位的有限脉冲响应（FIR）型抗混叠数字滤波器,得出了幅频特性和相频特性,满足了表面测量信号处理的要求．与传统的单纯模拟抗混叠滤波器相比,该方法有效降低了对模拟滤波器的设计要求,使其易于实现,滤波效果好．把该方法应用于表面测量系统中,通过对实测数据的应用试验,验证了滤波器的性能．     

线性相位有限冲激响应滤波器的实现

介绍线性相位滤波器的一种实现方法,即采用有限冲激响应（FIR）滤波器的窗函数法设计线性相位的数字滤波器。     

三维目标倾角不变光学模式识别的计算机模拟

研究了在传统的光学相关系统中，用一组滤波器实现三维目标倾角不变模式识别的方法，以及滤波器组的设计原理，获得了滤波器组的参数，完成了光学相关的计算机模拟。     

基于综合EDA技术的FIR数字滤波器的设计与仿真

数字滤波是数字信号处理领域中的关键技术之一,FIR数字滤波器是实现数字滤波的主要途径。基于综合EDA技术,设计特定性能指标的FIR数字滤波器的整体电路,并基于QuartusⅡ等软件平台对设计结果进行了交互式的仿真验证。仿真结果表明,所设计的FIR数字滤波器达到了指标要求,这种基于综合EDA技术的设计方法也使得数字信号滤波系统的开发更为可靠、便捷。     

Particle swarm optimization-based approach for optical finite impulse response filter design

This study presents what is to our knowledge a new and efficient method for the design of an optical finite impulse response (FIR) filter by employing a particle swarm optimization technique. With the method proposed, the design of an optical FIR filter, which is able to provide an arbitrary spectrum output based on crystal birefringence, could be implemented with good performance and high efficiency. The design procedure is discussed. A typical example of a green/magenta filter used in a liquid crystal on silicon projection display is included to demonstrate the feasibility and efficiency of this method in this design process as compared with simulated annealing.     

Design of linear phase FIR notch filters

This paper investigates some approaches for designing one-dimensional linear phase finite-duration impulse-responses (FIR) notch filters, which are based on the modification of several established design techniques of linear phase FIR band-selective filters. Based on extensive design examples and theoretical analysis, formulae have been developed for estimating the length of a linear phase FIR notch filter meeting the given specifications. In addition, the design of two-dimensional linear phase FIR notch filters is briefly considered. Illustrative examples are included. This work was supported in part by a University of California MICRO grant with matching supports from Rockwell International and CES Inc.     

基于FIR 数字滤波器的扫描图像去网

针对扫描图像,提出了一种基于FIR 数字低通滤波器的去网方法,该方法是将图像从空间域转换到频率域,对频率域图像进行FIR 低通滤波处理,结合图像评价指标PSNR,选择最优的滤波器参数。用该去网算法与常用的去网算法进行了比较,结果表明,该去网算法在达到去网效果的同时能够更好地保留边缘信息。     

Elimination of zero-order diffraction and conjugate image in off-axis digital holography

The presence of zero-order diffraction and a conjugate image in digital holography essentially diminishes the quality of the reconstructed image. In this paper, a novel method that adopts numerical operation to eliminate the zero-order diffraction and conjugate image is presented. The whole process needs only one hologram and a complex finite impulse response (FIR) digital filter. The method of numerical elimination is simple; it filters the hologram directly in the spatial domain instead of in the frequency domain. The design of a complex finite impulse response filter is described in detail. The experimental results demonstrate that the operation can completely eliminate the zero-order diffraction and conjugate image and significantly enhance the quality of the reconstructed image.     

First-order PMD compensation using optical FIR filter

We present a synthesis algorithm to design an optical finite impulse response (FIR) filter for compensating a first-order polarization mode dispersion (PMD) by minimizing the differential group delay (DGD). The desired frequency response was approximated using two widely used methods in designing digital FIR filters: the Fourier series expansion method and the frequency sampling method. A numerical simulation was performed for an eighth-order filter to demonstrate the difference between the two methods. The simulation results produced a sharper cutoff for the Fourier series expansion and higher stopband attenuation for the frequency sampling method. The Fourier series method produced better results in reducing the DGD.     

Implementation of broadband low-sidelobe beamforming in time domain

In modern active and passive sonar systems, broadband beamforming for acoustic arrays is widely used to suppress unwanted interference and to detect target signals of interest. A broadband low sidelobe beamforming scheme in time domain is proposed in this paper. The first step of this scheme is to delay the outputs of each element in the acoustic array by a tapped-delay-line (TDL) to accomplish the integer part of the time delay need to form a beam. Then, finite impulse response (FIR) digital filters are used to implement the fractional part of the time delay. The weighting coefficients for all array elements at different frequencies to realize the low sidelobe beams are also implemented with the FIR digital filters. Finally, the outputs of the digital filters are summed up to yield the time domain beam output. The design of low sidelobe beam pattern and that of the FIR digital filters are two crucial technical issues in this beamforming procedure. The low sidelobe beams of each sub-band are designed using the optimized beam synthesis approach based on the principle of MVDR beamforming. An improved adaptive approach are used for the design of FIR digital filters, and the design requirements of these filters were specified by the weights of low sidelobe beams of each sub-band over the broad frequency band. Results of computer simulation for a twelve-element arc array show that the beamforming scheme is very effective in forming low sidelobe broadband beam.     

The Direct Solution of Nonconvex Nonlinear FIR Filter Design Problems by a SIP Method

FIR filter design problems in the frequency domain are nonlinear (semi-infinite) optimization problems. In practice, however, these almost always have not been approached directly, but been solved in a simplified form and/or only under restricting assumptions. In this paper, quite general mathematical formulations of the four main design approximation problems in the frequency domain are presented, which enable the derivation of theoretical results (collected here from R. Reemtsen, 2000b, 2000c) and the application of general-purpose optimization procedures to their direct solution. For the actual solution, a nonlinear semi-infinite programming method from the thesis (S. Görner, Ph.D. Thesis, Technische Universität Berlin, Berlin, 1997) of the first author is discussed and applied to several specific design problems. In some cases, the computed solution of the nonlinear problem is compared with that of a convex approximation of the problem.