EMI专用元件的选择和使用

电子产品的电磁兼容性已日益受到生产了厂家的重视，但很多厂家在解决产品的电磁兼容性时常常不知该选向种元件来解决所存在的电磁兼容性问题，有时虽使用了电磁兼容性专用元件，但效果交并不理想，本文就ＥＭＩ专用元件种类，性能，适用范围和使用方法等问题进行了论述。     

EMI专用元件的选择和使用

ＥＭＩ专用元件的选择和使用张志华概述电子产品的电磁兼容性已日益受到生产厂家的重视，但很多厂家在如何选用专用元件来解决产品的电磁兼容性问题时却常常显得束手无策，有时虽使用了电磁兼容性专用元件，但效果并不理想。因此，这里有必要对这些问题进行探讨。近几年来...     

EMI对策元件和电路保护元件的发展与应用

本文简要介绍了EMI对策电子元件和过电压、过电流、过热电路保护元件的一些新进展及其应用状况。     

EMI对策元件和电路保护元件的发展与应用

简要介绍EMI对策元件和过电压，过电流，过热电路保护元件的一些最新进展及其应用状况。     

汽车系统电源监控器的选择和使用

汽车电源系统面临着诸多的挑战，这使得汽车电子产品的设计变得更加困难。在这些挑战中，首屈一指的就是电池系统有可能使由其供电的电子元件承受非常宽的电压和动态范围。根据环境的不同，一个电子元件可能要承受从-14V（如果电池极性倒置）到60V（负载突降过程中）的电源电压，而且经历这些电源电压后，电子元件要完好无损。而当需要考虑成本和效率时，这将成为一个难以实现的要求。     

EMI测量仪器的选择和使用

分析了CISPR 16-1-1对EMI测量接收机指标要求,从结构和测试使用上来区分频谱分析仪与测量接收机,使读者加深对测量仪器参数的理解,正确选择EMI测量仪器.同时通过介绍连续骚扰测试方法,详细说明了频谱分析仪和接收机在使用上的不同.     

基于EMI电源滤波器的设计和研究

为了避免设备及电网之间的相互干扰,可以应用滤波器,将其安装在电源入口处,设备工作频率可以通过滤波器,同时损耗高频率干扰,实现干扰抑制作用。文章以开关电源为例,探讨了EMI电源滤波器的设计问题,明确了滤波器件的高频特性,并建立了EMI电源滤波器的仿真模型,经过仿真实验和实际测试验证了E M I电源滤波器设计的科学性和正确性,最后分析了E M I电源滤波器的安装要点,旨在为相关研究和实践提供参考。     

选择正确的DC/DC转换器拓扑

基于电子设备的处理器系统设计人员经常在选择最佳电源架构时遇到困难。有时最佳的解决方案是插入式电源,而有时采用分立的元件组成的电源才是最佳解决方案。选择插入式电源解决方案相对来说比较直接,但对于缺乏电源设计经验的数字设计人员来说,设计一个分立电源解决方案可能会使他望而却步。大多 DC/DC 电源控制 IC 供应商均可提供有助于电路设计的详细辅助材料。但是,在开始电源设计之前,设计人员必须选择正确的拓扑。本文将介绍以下方法,来帮助为某些用于MCU、DSP及基于FPGA 的电子产品的最常用结构选择正确的电源拓扑。线性调节…     

高效率和低EMI二极管

Qspeed二极管采用独特的硅基工艺,兼具一个极低的反向恢复电荷（Qrr）和一个极软恢复波形。这些先进特性能够帮助设计师优化其电源转换电路的效率和EMI性能。Qspeed二极管非常适用干连续导通模式（CCM）升压式功率因数校正（PFC）电路,并在硬开关应用中用作输出二极管。     

电子产品EMI／RFI衬垫选择——EMI屏蔽衬垫技术仍是材料发展的焦点

理论上所有的电子设备应该在EMC状态下正常工作，无来自其它源的干扰或干扰其它设备，但EMI干扰常常发生而且降低电子设备的性能。自从电子时代开始，EMI就一直是一个问题，当前电子设计趋势向重量轻、体积小、功能多，由此带来的EMI问题已摆在最前沿。典型的是塑料壳体，这些产品需要薄、软、复杂形状的衬垫提供高屏效。     

正确的印制电路板布局可改善动态范围

谐波失真极低的现代IC放大器，在一系列应用中可以改善动态范围。但是，要特别注意这些放大器在印制电路板上的布局，因为不当的印制电路板布局可以使失真性能恶化20dB。     

EMI测试中几种测试参数选择问题的探讨

本文讨论电磁干扰自动测试系统中接收机带宽、检波器功能、步进衰减器的选择.最后提出了测试规则.     

浅析频谱分析仪和EMI接收机

详细阐述了频谱分析仪和EMI接收机的基本原理、使用方法和种类,并对两者进行了对比分析。对从事电磁兼容测试人员具有一定的参考作用。     

利用独立成分分析的高光谱图像波段选择方法

提出一种适合目标探测的基于独立成分分析(ICA)的高光谱图像波段选择方法。首先进行"虚拟维"(VD)估计以确定重要独立成分个数,同时对FastICA生成的独立成分排序,选择排序靠前的几个独立成分作为重要独立成分;再根据波段对重要独立成分的平均贡献量对波段排序;最后使用光谱相似性度量去除排序后的冗余波段,保证了最终波段子集含有较多的目标信息。对AVIRIS获取的两幅真实高光谱图像进行了目标探测实验,结果表明,文中方法优于另外两种基于二阶统计特性的波段选择方法,其选出的波段分别占据全部波段的12%和3%,目标探测算子自适应余弦估计(ACE)和自适应匹配滤波(AMF)其上的探测率较全波段分别提高了30%和15%。     

电源线滤波器与电磁干扰

文章主要从电源线滤波器的基本原理阐述了电源线滤波器对电磁干扰的抑制作用.并且详细阐述了使用电源线滤波器时应考虑的主要参数、体积大小的影响因素、实际滤波器与理想滤波器的区别,以及电源线滤波器的正确安装.     

Analog active filter component selection with nature inspired metaheuristics

The most crucial design step for analog active filter design is the optimal selection of passive component values due to manufactured constants. Since the search on possible combinations in preferred values for capacitors and resistors is an exhaustive process, it has to be automated with high accuracy within short computation time. In this work, two nature inspired metaheuristics, differential evolution (DE) and harmony search (HS) algorithms are utilized for optimal filter design considering different topologies and manufacturing series. Simulation results show that as global optimization methods both DE and HS minimize the total design error and reduce the elapsed time with respect to previously utilized methods.     

Web service selection algorithm based on principal component analysis

Existing Web service selection approaches usually assume that preferences of users have been provided in a quantitative form by users. However, due to the subjectivity and vagueness of preferences, it may be impractical for users to specify quantitative and exact preferences. Moreover, due to that Quality of Service (QoS) attributes are often interrelated, existing Web service selection approaches which employ weighted summation of QoS attribute values to compute the overall QoS of Web services may produce inaccurate results, since they do not take correlations among QoS attributes into account. To resolve these problems, a Web service selection framework considering user’s preference priority is proposed, which incorporates a searching mechanism with QoS range setting to identify services satisfying the user’s QoS constraints. With the identified service candidates, based on the idea of Principal Component Analysis (PCA), an algorithm of Web service selection named PCA-WSS (Web Service Selection based on PCA) is proposed, which can eliminate the correlations among QoS attributes and compute the overall QoS of Web services accurately. After computing the overall QoS for each service, the algorithm ranks the Web service candidates based on their overall QoS and recommends services with top QoS values to users. Finally, the effectiveness and feasibility of our approach are validated by experiments, i.e. the selected Web service by our approach is given high average evaluation than other ones by users and the time cost of PCA-WSS algorithm is not affected acutely by the number of service candidates.     

EMI快速诊断与对策

文章主要介绍了EMI快速诊断与对策实例，指出EMI改进的关键是EMI问题诊断，解决电磁兼容问题的根本办法是进行电磁兼容设计。     

A hybrid genetic algorithm for analog active filter component selection

Analog filters are circuits that process electrical signals on a frequency-dependent basis. Analog filter circuits can be implemented using resistors, capacitors and inductors and they can also be implemented with only resistors and capacitors with the use of active circuit equipments. The selection of optimum component values is difficult because of the number of possible filter combinations. This paper presents an effective algorithm that hybridizes the Genetic Algorithm (GA) to form a Hybrid Genetic Algorithm (HGA) and proposes the use of Tabu Search (TS) for the analog active filter component selection. The GA has a powerful global searching ability and so is used to perform exploitation and because TS also has good local searching ability, it too is applied to perform exploitation. Thus, the proposed HGA will have very good searching ability. In this study, a band-pass Sallen-Key filter circuit was used, and the filter component values were found using HGA with LabVIEW. The results are compared to other reported state-of-the-art algorithms, such as the artificial bee colony (ABC) and differential evaluation (DE) to demonstrate the effectiveness and efficiency of the developed method. It can be said that the developed LabVIEW based HGA gives satisfactory results with regard to amplitude response, the minimum fitness values and the computational time.