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通过对共模电流辐射的介绍和详细技术分析,有针对性地讨论了面向产品设计的共模电流辐射控制手段,并简单介绍了共模电流的近似测量,为工程师进行电子/电气设备的电磁兼容设计提供有价值的参考。 相似文献
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电子设备特别是中长波段无线电接收机电磁干扰问题,一直是困扰接收机灵敏度提高的难点,当前电子设备的小型化使干扰源与敏感单元距离越来越小。针对新研制接收机生产过程中的一起电磁干扰问题,分析了电磁干扰的产生和危害,采取电路分割排除法和组件移动法,查找到了产生电磁干扰的源头,为接收机电源部分裸露的共模扼流圈产生辐射干扰。针对电磁辐射干扰源特点,对共模扼流圈采用电磁屏蔽技术,解决了接收机电磁干扰问题。 相似文献
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连接电子设备的接口电缆中的屏蔽层,起着天线的作用,会引起共模辐射。作为对策,我们在电缆护套内添加磁性损耗层,开发出DAISET-F电缆。 相似文献
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不同差分传输线线形对信号完整性的影响 总被引:1,自引:0,他引:1
因为低辐射和对共模噪声有较好的抗干扰能力,差分信号被越来越广泛的运用。但是由于传输线的线形不一致,使得差分信号之间产生了相位差,从而产生了共模噪声并增加其辐射发射。文中讨论了四种不同的差分线线形,利用S参数分析了它们的共模噪声,并提出了两种减小共模噪声的方法。 相似文献
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线形结构对差分传输线信号完整性的影响 总被引:1,自引:1,他引:0
在高速PCB设计中,随着电路传输速率的增长,差分信号被越来越多地运用到布板中.在实际走线中,由于线形结构的不一致,使得差分信号之间产生了相位差,从而产生了共模噪声并增加其辐射发射.为了减小差分传输线的共模噪声对信号完整性的不利影响,文中分别讨论了直角、斜接、圆角和45°角4种不同的差分传输线拐角线形,在HFSS中建立了三维物理模型,利用S参数分析了它们的共模噪声,得出了45°拐角为布线最优选择.并提出了减小其共模噪声的方法. 相似文献
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本文研究了场线路多耦合下电机及其驱动系统辐射电磁干扰预测方法.共模干扰回路是系统产生电磁辐射的主要来源,分析了系统共模干扰源的产生机理和传导路径.建立了共模干扰传导路径中主要部件的模型,即交流感应电机等效电路模型及驱动系统输入输出屏蔽电缆线束模型等,将各部分电路模型按照实际连接情况进行组合,获得了系统辐射电磁干扰预测模型.提出了利用CST MWS和CST CS对预测模型联合仿真的分析方法,并通过实验验证了预测模型的正确性. 相似文献
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计算机视频屏蔽电缆的电磁泄漏* 总被引:2,自引:0,他引:2
本文对视频(屏蔽)电缆的辫接效应(Pigtail Effect)及其辐射机制,进行了理论和实验研究;利用天线和传输线理论提出了屏蔽电缆共模辐射的物理模型和数学公式;分析和验证了辫接效应是导致屏蔽电缆产生辐射的主要诱因;提出了防护和抑制这种共模辐射的原理和手段。 相似文献
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Common-mode radiation, which is often the predominant contributor to the overall radiation from circuit boards and electronic hardware, has in the past been difficult to calculate. Since the return paths for common-mode currents are not obvious, all parasitic circuit elements must be properly taken into account. The authors calculate the radiation, which includes both differential and common-mode components, from arbitrarily shaped 3-D conductor-dielectric composite structures using a full-wave approach. Excellent agreement between measured and calculated results is demonstrated. Further, a great deal of insight into the mechanism for generation of common-mode current, and hence radiation, is obtained 相似文献
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高速电路的高频辐射和信号完整性问题极大地影响了电子设备的电磁兼容性。本文从高速电路的传输特性入手分析讨论影响电磁辐射的几大因素,以凌动(ATOM)平台图形终端为例,给出了印制板设计上的可行方案,验证了高速电路电磁兼容设计的基本原则。 相似文献
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Hockanson D.M. Drewniak J.L. Hubing T.H. Van Doren T.P. Fei Sha Wilhelm M.J. 《Electromagnetic Compatibility, IEEE Transactions on》1996,38(4):557-566
Fundamental EMI source mechanisms leading to common-mode radiation from printed circuit boards with attached cables are presented in this paper. Two primary EMI source mechanisms have been identified: one associated with a differential-mode voltage and another associated with a differential-mode current, both of which result in a common-mode current on an attached cable. These mechanisms can he used to relate printed circuit layout geometries to EMI sources. The two mechanisms are demonstrated through numerical and experimental results, and an example from a production printed-circuit design is presented 相似文献
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EMI(电磁干扰)问题的深入研究对提高所设计产品的可靠性有着较大的现实意义。文中阐述了EMC(电磁兼容性)在电路设计中的重要性和电子设备的EMC问题。就雷达发射机的EMC设计问题,根据发射机干扰信号的传播途径和耦合方式,针对经常出现的各种EMI问题,提出了接地、屏蔽、滤波、瞬态抑制等4种抑制EMI的方法。介绍了其他一些常用的提高设备EMC的方法,分别从PCB(印制电路板)设计、设备内的布线、软件抗干扰设计等方面进行了探讨。 相似文献
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A study of the common-mode radiation behavior of differential signalling is presented, considering small current imbalances, which may originate from differential driver phase skew and circuit asymmetries. Two configurations are investigated, a solid ground plane and a ground plane with an open slit as an example of a ground-plane discontinuity. The external coupling voltage responsible for common-mode radiation is quantified through coupling inductances, for which closed-form expressions are derived and numerically validated. It is found that common-mode electromagnetic interference from differential signalling may become comparable to conventional single trace routing when traces are placed near the edge of the ground plane. For traces routed across a ground-plane discontinuity, differential signalling is only an effective means for reducing radiation when signal imbalance can be kept small. 相似文献
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FDTD modeling of common-mode radiation from cables 总被引:4,自引:0,他引:4
Hockanson D.M. Drewniak J.L. Hubing T.H. Van Doren T.P. 《Electromagnetic Compatibility, IEEE Transactions on》1996,38(3):376-387
Radiation from cables attached to printed circuit boards and shielding enclosures is among the primary concerns in meeting FCC Class A and B limits. The finite-difference time-domain (FDTD) method can be employed to model radiation from printed circuit boards and shielding enclosures with complex geometries, but difficulties in modeling wires and cables of arbitrary radii are encountered. Modeling the wire by setting the axial component of the electric field to zero in the FDTD method results in an effective wire radius that is determined by the mesh discretization. Neglecting the wire radius in applications, such as electromagnetic interference (EMI) or printed circuit board modeling, may result in gross errors because near-field quantities are typically sensitive to wire thickness. Taflove et al. (1988) have developed a subcellular FDTD algorithm for modeling wires that has been shown to work well for plane wave scattering. The method uses a quasistatic field approximation to model wires with a well defined radius independent of the mesh dimensions. The wire model is reviewed and investigated for application to common-mode radiation from cables attached to printed circuit boards, where the source is often a noise voltage at the connector. Also investigated is energy coupling to attached cables through enclosure apertures resulting in common-mode radiation from the cable. The input impedance for a center-fed dipole antenna, as well as a monopole connected to a conducting half-sheet, is computed with FDTD methods and compared to moment method input impedance results. A simulation of a shielding enclosure with an attached cable demonstrates the utility of FDTD analysis in modeling common-mode radiation 相似文献
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针对电子设备特别是手提电子设备对电子元件小型化、集成化的要求,提出了如何设计印刷电阻、印刷电容、印刷电感的方法,重点给出了计算印刷电路板电感的计算公式,并构建了其电路模型。实验证明理论计算值与实际值的一致性。 相似文献
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现代工艺集成电路的总剂量效应及加固技术 总被引:1,自引:0,他引:1
随着核技术和空间技术的发展,越来越多的电子设备不可避免地应用于各种辐射环境中。介绍两类重要的辐射环境及现代工艺集成电路总剂量效应的产生机理,详细描述电子空穴对的产生、氧化层陷阱电荷和界面陷阱的特点及对器件或电路的影响,并对现代先进工艺的抗辐射特点及应用前景进行了探讨。指出随着CMOS工艺不断按比例缩小,作为栅介质;HfO2最具应用前景,而Smart—Cut材料则是非常有发展前景的SOI材料,很可能成为今后SOI材料的主流。 相似文献