高速PCB板的电磁兼容设计

以某一嵌入式系统核心PCB板设计为例，介绍了电磁兼容的基本概念及一些高速PCB板设计的基本知识，着重分析了无高频器件时高速PCB板设计中存在的电源系统干扰、地线噪声干扰和信号线阀的串扰等电磁干扰，并分析了这些电磁干扰产生的主要原因，从PCB总体设计和元器件布局、布线等方面考虑，对可能存在的这些干扰，提出了防止和抑制方法以及一些提高PCB板电磁兼容性的具体措施；在工程实践中证明这些方法和措施有效可靠。     

高速PCB电磁兼容性设计

讨论了在高速PCB设计中电磁干扰的产生原理，阐述了提供低阻抗的射频电流回路、避免串扰等抑制电磁干扰的措施来满足PCB的电磁兼容性。对高速PCB设计有一定的指导作用。     

PCB电路设计中布线的EMC分析

本文着重考虑了现代PCB电路设计中的电磁兼容问题，分析了PCB电路中布线的电磁干扰问题，从单线，多导体线及元器件的布局和走线出发，给出PCB电路中布线的一些设计原则和技术规范，PCB电路设计工程师在电路设计之初运用这些原则规范能够很好的解决布线的电磁干扰问题。     

射频电路PCB板的电磁兼容性设计

从PCB布局、PCB布线（电源线、地线、时钟线及信号线的最优化布线原则）和补铜箔等几个方面讨论了在PCB设计中如何抑制射频干扰及实现系统电磁兼容性的方法，实践证明，该方法在抑制电磁干扰方面是比较有效且非常经济的。     

印制电路板电磁兼容设计浅析

文中介绍了印制电路板上电磁干扰辐射产生的主要原因,并对其产生的机理进行了详细的研究和分析,得出了能够减少电磁干扰的几种方法。在印刷电路板设计中,对单面板的线路板迹线的阻抗和PCB布线的分析以及对双层PCB板的设计分析,基本保证了印电路板的质量与可靠性,并减小了电肱干扰的影响。最后,通过对地线网络、地线面、输入输出地的结构、地线布线规则等几种接地方式进行较为详细的研究与分析,得出了进一步减小电磁干扰的方法。     

PCB电路设计中布线的EMC分析

PCB电路设计在生产生活中至关重要,本文从电磁兼容这一问题出发,讨论PCB电路设计,以及在设计PCB电路过程中存在的电磁干扰等问题.分析单线,多导体线和元器件的设置、路线,从而得出关于PCB电路中布线的一些设计规范和技能.如果将这些原则和规范使用于电路设计的最初环节,那么存在于布线中的电磁干扰问题就会被PCB电路设计师很快的解决.     

半桥QRC印制板的电磁兼容研究

以半桥ZVS准谐振变换器作为研究对象,借助Cadence软件对开关电源PCB进行了建摸分析、提取寄生参数和电磁兼容仿真分析,并进行了优化布局设计。实现了开关电源PCB的计算机辅助电磁兼容分析和计算机辅助最优布局设计,从而可以在PCB设计阶段就对其潜在的电磁干扰源进行抑制,为开关电源电磁干扰的解决和PCB电磁兼容设计提供了一种较为合理有效的研究思路。     

PCB电磁兼容设计对整机性能的影响

介绍了电磁兼容、电磁干扰;着重介绍了电磁兼容设计中,解决自我兼容性问题的手段与措施,对PCB设计中的布局与铺地的重要性,以及需遵循的基本原则进行了较全面的阐述。通过实践案例说明PCB设计对整机性能,再次提醒读者关注PCB的布局与铺地问题。     

印制电路板的电磁兼容性预测

以有限元数值计算方法和SPICE仿真软件为工具，通过对印制电路板（PCB）耦合微带线的电磁兼容性预测，来对具有不同厚度PCB的电磁干扰水平进行估计分析。并对利用屏蔽地线低频信号迹线和高速数字信号迹线分开来降低EMI水平的方法给以预测评估，最后归纳总结出影响PCB电磁兼容性能的因素，提出PCB设计中电磁兼容性（EMC），适应性方法的指导性原则，为PCB的电磁兼容性设计提供参考依据。     

DVD数字视盘机电磁干扰设计

电磁干扰是电子产品一个不容忽视的问题,在设计时就应该采取措施,良好的设计将减少设计时间和产品成本.从国家标准化组织对电磁干扰的要求出发,分析了数字视盘机产生电磁干扰的三个主要原因,由此有针对性的从开关电源、音频/视频输出和PCB电路板三个方面展开讨论,设计分析了抑制电磁干扰的几种方法,并通过了EMI测试.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.