一种新型伪镜像滤波器组的实现方法

本文提出了一种新型２Ｍ个通道伪镜像滤波器组的结构和设计方法。本设计方法中，低通原型滤波器采用两级级联线性相位ＦＩＲ的结构，并使得整个分析／综合系统性能近于全恢复，无群时延失真。应用此方法设计伪镜像滤波器组，分析和综合滤波器组的结构和设计方法都比较简单，算法效率高，实现比较容易，这类滤波器组可用于语音的子带编码等。本文最后给出了一个实例。     

开关电容阵列滤波器的设计

本文论述了开关电容阵列滤波器的设计．它可以通过改变一块铝版使同一块模版布局不同种类和不同性能指标的开关电容滤波器，从而可以用计算机辅助的半定制设计方法设计，缩短了设计周期，并满足多用户对开关电容滤波器不同品种与性能指标的要求，降低了生产成本，便于大规模生产．     

一种通用的E面波导滤波器数值分析方法及其CAD软件包

本文提出了一种通用的数值方法，该方法可用于分析各类不同的波导Ｅ面滤波器。根据这种方法，开发了基于Ｍｉｃｕｏｓｏｆｔ Ｗｉｎｄｏｗｓ的ＣＡＤ软件包ＥＦＩＬＴＥＲ。利用这个软件包分析了各类Ｅ面滤波器，所得结果与其它方法计算结果和实验数据吻合甚好。此外还分析了几种新Ｅ面结构滤波器．     

时变级联滤波器的两种设计方法

本文针对雷达杂波抑制中常用的时变级联滤波器，提出了两种实用的设计方法。第一种方法通过时变级联滤波器与时变非级联滤波器的等效来设计时变级联滤波器。该方法可以使用变级联滤波器具有最佳波滤波器的效果。第二种方法通过对总的等效滤波器的设计来得到级联滤波器第二级的权系数。分析表明，时变级联滤波器第二级的频率中央响应很难写出，但可以通过总的等效频率响应来体现。     

数字信号处理的现代滤波器

本文叙述用数字信号处理方法所构成的滤波器的基本组成，原理，电路，制作要求和检修方法。     

新型多功能开关电流双二次滤波器

本文提出了一种具有较低灵敏度和正反两相输出的开关电流（ＳＩ）改进型通用积木块（ＭＵＢ）可以实现抽样数据信号处理的各种基本运算，据此，以开关电容电路为原型，采用信号流图方法生成了一种新型Ｓ高Ｑ双二次滤波器，可获得低通，高通，带通和带阻等多种滤波的能。     

滤波器电路的计算机辅助设计综述

本文综述了集总参数元件滤波器电路的计算机辅助设计的发展及目前的状况。首先讨论了滤波器传输函数的逼近及机助设计情况，列出了有关带有程序清单的参考文献；然后指出了ＬＣ滤波器机助设计中的难点及解决的办法，并给出了简单滤波器设计的显式公式。对于有源滤波器的机助设计，文中分析了有源滤波器ＣＡＤ的发展及现状，阐述了开发有源滤波器设计程序所遵循的原则，对于数字滤波器，文中回顾了ＩＩＲ和ＦＩＲ数字滤波器机助设计的情况，并阐明了正交镜像滤波器的机助设计方法。     

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／前馈差分器来设计开关电流高通梯形滤波器，这种ＢＦＤ是用本文提出的ＳＩ模块，通用差分器构成，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高通滤波器和椭圆高通滤波器设计的实例。     

光纤环形延迟线陷波器最佳陷波的实现及PIIN的影响

本文研究了ＰＩＩＮ的时，频响应特性，得到了它作为陷波器的最佳陷波条件，提出了利用环路损耗调节器性能，实现最佳陷波特性的方法，采用该方法使ＦＯＲＤＬ的陷波深度达到了６５ｄＢ，同时，本文还研究限制ＦＯＲＤＬ最佳陷波特性实现的主要系统因素－相位感生的强度噪声（ＰＩＩＮ）给出其在单模条件下的频率特性，由此出发，分析了影响ＰＩＩＮ的几个因素，提出了抑制ＰＩＩＮ的三个途径：（１）采用极化控制器适当调节两个正交     

通用射频滤波器的设计与实现

阐述了射频滤波器在电子、通信工程中的应用。介绍工程化的射频滤波器的研制步骤和设计技术，着重介绍了应用专用的电子线路CAD软件进行滤波器设计的方法，并且给出了制作过程中的注意事项和实用技巧。     

基于KD树的射线跟踪法计算飞行器RCS

利用几何光学射线跟踪法对飞行器整体目标雷达散射截面(Radar cross section,RCS)进行估算,假设入射波为高频平面波,传播中符合几何光学定律,将入射波划分为平行入射线进行跟踪并进行口径积分。为减少射线与大型目标表面的求交计算次数,应用了KD树方法的基本原理,将飞行器目标表面划分多层子包围盒,设计了射线与子包围盒及面元遍历求交算法。应用文中方法计算了一种新型无人飞行器的RCS,计算结果与传统的RCS高频估算方法(PO方法)得到的结果以及实测结果进行比对。结果表明,文中方法较传统PO方法更接近实测结果,在飞行器RCS预估方面具有一定的应用价值。     

Effective-index method with built-in perturbation correction forintegrated optical waveguides

It is well known that the conventional effective-index method for the analysis of rectangular-core waveguides can in general produce accurate results only when the modes of the waveguides are operated in the far-from-cutoff region. In this paper, an improved effective-index method, called the effective-index method with built-in perturbation correction, is described. This method is as efficient as the conventional method pet produces much more accurate results. Numerical examples for single waveguides and directional couplers are presented to demonstrate the accuracy of the method with results obtained from an improved Fourier decomposition method as the references     

平板缝隙天线的计算机辅助设计

基于边值积分方程方法的小型平面缝隙阵的机助设计方法。这种计算方法是严格的。但即使对于小型阵，计算量也相当大。对小型阵提出缝列与耦合分支分别设计的方法，并给出模型实验结果。实验结果表明，对于一般指标的方阵，这种方法是可行的。对于低分瓣和超低旁瓣阵，尤其大型阵，还需以严格计算代替大量实验，去寻求简化计算的经验方法，建立一种半经验的机助设计方法。     

利用变径声粒子进行空间声场的仿真

为实现封闭空间声场的计算机模拟，在声线跟踪法基础上，提出了变径声粒子跟踪方法，该方法有效的解决了在经典声线中接收区域的选取影响仿真效果这一难题。在Visual Basic6.0的基础上编制了仿真软件，仿真实验结果表明，该方法是可行的。     

FINITE DIFFERENCE METHOD FOR ELECTROMAGNETIC SCATTERING FROM PERFECTLY CONDUCTING CYLINDER

A numerical method of solving electromagnetic wave scattering problem is described.Radiation boundary condition(RBC)is applied to confine EM scattering problem in unboundedregion into problem in finite region.Combined with RBC and scatterer surface boundary condi-tion,Helmholtz equation in the finite region is solved numerically by the finite difference method.Thus the distribution of induced surface current on conducting cylinder and near field can beobtained.Computational results for both polarizations for circular,elliptic and square cylindersare presented.These results are in excellent agreement with those obtained by the eigenfunctionexpansion method or moment method and much better then the results of OSRC method.     

Level set formulation for automatic medical image segmentation based on fuzzy clustering

The level set method is widely used in medical image segmentation, in which the performance is seriously subject to the initialization and parameters configuration. An automatic segmentation method was proposed in this paper, which integrates fuzzy clustering with level set method through a dynamic constrained term in the new energy functional. It is able to use the results of fuzzy clustering directly, which can control the level set evolution. Moreover, the added constrained term is changing continuously until getting the final results. Such algorithm eliminates the manual operation a lot and leads to more robust segmentation results. With the split Bregman method, the minimization of the new energy functional is fast. The proposed algorithm was tested on some medical images and also compared with other level set models and the state-of-the-art method such as U-Net. The quantitative and qualitative experimental results show its effectiveness and obvious improvement for medical image segmentation.     

Numerical evaluation of Rayleigh hypothesis for analyzing scattering from corrugated gratings--TE polarization

Diffraction of parallel polarized electromagnetic waves from corrugated periodic perfectly conducting surfaces is analyzed by both a rigorous method and a method based on the Rayleigh hypothesis. The accuracy of the rigorous technique is established by comparing results against other theoretical and experimental results. Further results are then obtained and used as standards against which results based on the Rayleigh method are compared for accuracy. These comparisons indicate that the Rayleigh method gives reasonably accurate results for gratings with surface height to period ratios of up to0.88/(2pi). This confirms that the Rayleigh method is also applicable to these nonanalytic surfaces and leads to accuracies that are higher than those normally assumed in the literature.     

Fougere method applied to antenna data

In the letter the performance of the Fougere method for autoregressive (AR) spectral analysis is studied. This method is compared with the Burg method and the least-squared (LS) method (Marple algorithm). It is shown that when the signal consists of two equal-level sinusoids in white noise and the data are complex-valued, as they will be in antenna applications, the Fougere method improves the results obtained by the Burg method in all cases. Also, for low signal/noise ratio (SNR), the Fougere method gives better results than LSM.     

理想导电柱体电磁散射的有限差分法

本文提出一种新的求解二维电磁散射的数值方法。应用辐射边界条件将无限大空间的电磁散射问题限制在有限区域内,采用有限差分技术数值求解波动方程、辐射边界条件及散射体表面边界条件,从而获得理想导电二维散射体的表面感应电流及近场分布。本文给出的圆形、椭圆形及方形截面柱体的数值计算实例表明,这种方法可获得与本征函数级数解或矩量法解相当吻合的结果,大大优于表面辐射条件法的结果,表明这种方法可能成为代替现有解析或数值方法的有效方法。     

矩形波导纵向缝隙的矩量法分析

该文提供了对矩形波导纵向缝隙求解的更为精确的矩量法分析,同时考虑了缝隙电场的横向分布特性和波导壁厚的影响。对缝隙的谐振长度进行了实例计算,对比实际测量和软件仿真结果,具有很高的精确度。随后对算法的收敛性进行了分析,发现该文算法在基函数取到20,模式数取到2020时基本收敛。该文还对缝隙电场横向分布特性在计算缝隙谐振长度时的影响进行了分析,结果表明其在半高波导、大缝隙偏置、大缝隙宽度和窄壁厚这几种情况下影响比较大。