We often wonder how good you are. Want to start a heated argument in the EMC community? Just start talking about grounding systems and why the Star or single point ground (SPG) system is so-o-o-o much better than those ridiculous multipoint ones being used by all those other people. Really? Are they that good? Before I answer that, let me first mention Scott … [Read more...]
Grounding Conductor Limitations!
I briefly mentioned some of the elements of grounding in the last post. Technically, there are three types of grounding systems that work: (1) the single point (a.k.a. star) ground (SPG), which uses wires; (2) the multipoint ground (MPG), which requires a ground plane or mesh; and (3) the floating (no) point ground (FPG). All three utilize some variety of RF … [Read more...]
Common Mode Emission. Can It Get Any Worse?
You betcha! Once upon a time I was in charge of EMC design for a large scale military digital telecommunications system. This system had to handle both red and black analog and digital data with the proviso that never the twain shall meet. In the lab where all the engineering tests were taking place everything went great until the cables were hung on the … [Read more...]
可形成局域网连接并可用于充电的桌子
来自东京大学的研究人员在日本举行的日本高新技术博览会（Ceatec）电子展上展出了一种桌子，这种桌子能够为置于其上面的装置提供无线充电并在装置之间形成一个局域网。这一概念源自于支持无线专网的想法，这种网络比当前的Wi-Fi网络更安全、更为局域化，同时也不需要网线。 这种桌子由小网面板组成的薄板制成，这种小网面板在两个维度内含有电磁波，并携带一个较小的电流。东京大学的一名博士生Akihito … [Read more...]
What’s this about CM and DM radiation?
We’ve been discussing loops all along and we are still at it. The last post looked at DM, this time it’s back to CM. These loops are the worst -- big – bad – ugly! Finding the loop may be a problem . . . but where there’s current, there’s a loop. The DM loop is easy, typically a differential pair over a ground plane in a high-speed system, the CM is some … [Read more...]
Tell Me Again Ron – What’s This About CM & DM Radiation?
Apparently, I didn’t throw enough words at the CM/DM problem in the last several posts so I’m going to add to it, but from a slightly different perspective. It’s either that or hide my email address. I’ll do DM this time, CM next time. We’ve been discussing loops all along. If there’s current, there is a loop somewhere. Finding it may be a … [Read more...]
在高频段关键元件的评估和高电流的设计中穿心电容的精确测量
George M.Kauffman (乔治·考夫曼) 在几乎所有的低通滤波器中,并联电容器都是关键元件。穿心电容器具有的形式为一接地壳体中心有一电极穿过，从电极到接地外壳间形成它所需的电容值，几乎消除了引线电感的影响。本文将介绍穿心电容器的重要性，并给出改进的方法以实现对关键部件的高频性能测试。对于设计、应用条件、进货检验或质量审核中进行穿心电容的评估，需要用到一个可重复使用的装置来测试其插入损耗性能。高电流和高性能滤波器的测试对于元件测试具有特殊的挑战性。这里的高电流指的是额定电流大大超过30安培，并直到和超过400安培。高性能一般是指频率至少高达1GHz时，其插入损耗大于30dB。 图1 … [Read more...]
On Mismatch Error Estimation by Measurement of Radiated Disturbances
Jan Sroka Warsaw University of Technology Original article translated from Polish. Introduction The quantity of interest (measurand) by the measurement of radiated disturbances is either electric or magnetic field strength. It is detected with an antenna and converted to the signal in the 50Ω coaxial system. This signal is transmitted to the measurement receiver via coaxial … [Read more...]
凝胶剂涂层和黏结剂涂层包装载体的对比研究
Robert J. Vermillion：来自美国加利福尼亚州莫菲特菲尔德市美国国家航空航天局（NASA）埃姆斯研究中心， RMV科技集团有限责任公司；Doug Smith：来自美国加利福尼亚州洛斯加托斯市的DC Smith咨询公司。 多年来，静电放电（ESD）时的敏感器件，在分发、储存和出售过程中使用凝胶剂和黏结剂涂层包装材料是否合适的问题，半导体和航空工程师们已经给出了答案。既然这种包装类型经常用于无电离的ANSI/ESD S4.1-2006 规定的ESD敏感器件工作表面，那么问题就出现了：这种铆定组件无需特殊设计的包装或电离的做法，是否能构成保护超敏感0级 … [Read more...]
不再需要为核电站设立禁区
Philip F. Keebler, EMC Group, Electric Power Research … [Read more...]
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