电磁兼容屏蔽测量技术

当今各种电子、电气设备已广泛应用于人们的日常生活, 随着电气与电子工程技术迅速发展,电磁噪声和电磁干扰问题逐渐引起人们的高度重视,因此,进行电磁兼容测量和实验成为一项非常重要的工作,世界各国都在不断加强电磁兼容技术方面的研究.早期的电磁兼容辐射发射和敏感度测量在开阔场进行,但是随着环境电磁噪声的不断增强,很难找到符合标准的开阔地,近年来,屏蔽测量技术得到了较快发展.本文讨论了电磁兼容测量中屏蔽测量技术的发展,介绍了屏蔽测量技术的原理、应用、现状以及发展趋势,供有关技术人员参考.随着各国对电磁环境重视程度的增加,电磁兼容测量技术将会得到更快的发展.     

The time-domain electromagnetic interference measurement system

A novel real-time broad-band time-domain electromagnetic interference (TDEMI) measurement system for the 30-1000-MHz frequency range is described. The signals from the antenna are sampled, analog-to-digital (A/D) converted and digitally processed. The fast-Fourier transform (FFT), the Welch- and Bartlett periodograms are digitally computed. Compared with state-of-the-art EMI measurement systems, the novel described TDEMI system samples the complete phase and amplitude information of the EMI simultaneously over the whole frequency band under consideration. With the presented time domain measurement system the measurement time can be reduced by a factor of 10. The digital processing of EMI measurements allows emulation in real-time of the various modes of conventional analogous equipment, e.g., peak, average, rms and quasi-peak detector and also introduces new concepts of analysis, e.g., phase spectra, short-time spectra, statistical evaluation and FFT-based time-frequency analysis methods.     

飞行器惯性测量组合的电磁敏感度评估

采用双因素等重复试验方差分析(ANOVA)方法实现对惯性测量组合的电磁敏感度试验评定.将惯性测量组合(IMU)参数标定测试与电磁敏感度试验相结合,克服了单独进行电磁敏感度试验难以区分评定等级的难题,从而获得参数标定位置因素与电磁干扰强度因素对惯性测量组合输出脉冲个数的单独影响和交互作用.     

基矛电磁波的低流速测量中干扰因素分析研究

介绍了电磁渡测量流速的基本原理一多普勒效应．分析了影响低流速测量的主要干扰因素一发射泄漏干扰和旁瓣干扰。根据接收信号中发射泄漏干扰不变的特性,提出了去均值滤波的方法来消除干扰,对数据进行预处理;根据旁瓣干扰的信号特性,提出了通过频谱加窗和二次加权平均法构造频域带通滤波器来抑制干扰的方法,在仿真比较完各个窗函数的性能之后,选定布莱克曼窗来进行频谱加窗。仿真分析表明,旁瓣干扰经频域带通滤波后得到了很好的抑制。最后通过实验测试验证了这些方法在流速测量中的显著效果。     

基矛电磁波的低流速测量中干扰因素分析研究

介绍了电磁渡测量流速的基本原理一多普勒效应．分析了影响低流速测量的主要干扰因素一发射泄漏干扰和旁瓣干扰。根据接收信号中发射泄漏干扰不变的特性,提出了去均值滤波的方法来消除干扰,对数据进行预处理;根据旁瓣干扰的信号特性,提出了通过频谱加窗和二次加权平均法构造频域带通滤波器来抑制干扰的方法,在仿真比较完各个窗函数的性能之后...     

Circuit modelling for electromagnetic compatibility

Sophisticated software is widely available in the form of mathematical and circuit analysis packages. This computing power can be harnessed to assess the electromagnetic coupling between signals in a system and currents in the structure. To achieve this objective, it is necessary to have reliable circuit models of the coupling parameters. A method of formulating such models is described, illustrating key relationships between circuit theory and electromagnetic theory. It is shown how general-purpose testing can be used to refine any model, and how the results of formal testing can be predicted     

Implications of the electromagnetic compatibility directive

The impact of the Electromagnetic Compatibility Directive on providers and users of electrical and electronic products is only starting to be appreciated by many of the very people who should by now have everything in place for 1st January 1996. This paper reviews the implications of the UK implementation of the Directive. All relevant products or systems supplied or brought into service from the end of 1995 are affected by the Directive, which must be complied with, otherwise serious criminal and civil penalties could result. The affixing of the CE-mark does not in itself assure adequate EMC performance of the product in each and every application     

低频/甚低频电磁脉冲测量系统研究

为了准确地测量电磁脉冲（electromagnetic pulse,EMP）的波形,开展低频/甚低频（low-frequency/very low-frequency,LF/VLF）EMP的形成和传播机理研究,识别不同EMP的特征,并以此为依据来识别、确认雷电及核爆炸等现象,提出了一种高分辨率的EMP原始波形测量系统方案,同时针对LF/VLF这一较低的频段提出了一套有效的系统标校方法,实现了对EMP的连续、准确测量和快速有效判别,并能通过网络实时上传数据.系统采用正交环磁场天线和平板电容电场天线实现信号的接收,设计了低噪声高保真的信道调理电路和高速数据采集电路来实现信号的采集,利用高精度的授时模块为EMP信号标记时间戳,最后结合多点监测波形实现EMP定位估计.实测结果表明:该系统能够给出高分辨率、高精度的LF/VLF EMP波形;利用该系统组网可以实现远距离EMP源的定位,定位精度与目前近距离的定位手段相当.通过长期的运行,验证了该系统具有高可靠、低失真、判别准确、实时性强等特点.     

传感器电磁兼容技术研究

应用于航空领域的传感器经常面临复杂的电磁环境,为了提高传感器的抗电磁干扰能力,同时不对其它设备形成干扰,需要对传感器进行电磁兼容设计。合理的设计方案,将显著提高传感器的电磁兼容性能。通过设计实例,提出了传感器应对电磁干扰问题的具体解决措施,通过试验验证,证明了设计方法的有效性。     

电子式互感器电磁兼容性能研究

随着现代科技的不断发展,人类的电子、电力技术已经有了质的飞跃,电子式互感器是目前监测电流的重要仪器。本文即是对电子式互感器电磁兼容性能进行的研究,为了提高这一装置的性能,提升其挂网运行的整体稳定性,按照国家标准规定对其就进行了强电磁干扰隔离开关容性试验,并且分析了该项实验的原理,并对各类试验研究结果进行相应的分析,以期能为相关工作提供参考。     

Pastes for electromagnetic interference shielding

A paste has been developed for electromagnetic interference shielding by mixing stainless steel fibers (8-μm diameter) and graphite flakes (5 μm) in a water-based graphite colloid (containing submicron graphite flakes and a binder) in a volume ratio 0.5:20:100. The resulting coating of thickness 0.1–0.2 mm after drying exhibits shielding effectiveness of 34 dB at 1 GHz, primarily due to reflection. The paste is superior to those containing graphite flakes or carbon filaments (0.1-μm diameter), due to the higher shielding effectiveness of the steel fibers. The graphite flakes in the paste serves to help suspend the steel fibers, in addition to contributing to shielding.     

核电环境电磁兼容测试方法研究

目前我国核电技术的发展迅速,而核电环境下的电磁兼容测试在我国一直处于空白?剖析了核电现场测试的目标,根据对GSM,Wi-Fi,CDMA2000,WCDMA, TD-LTE,FDD-LTE 等各种通信技术指标的分析结果,参照国外电磁兼容标准以及目前电磁兼容经验,提出了核电环境下的现场电磁兼容测试方法,同时根据测试结果,通过设定保护距离,锁定基站?终端功率等措施,保障核电系统设备的正常运行,也为后期的标准制定提供了试验依据?     

抑制电磁干扰源的设计

电子设备工作时,受到各种因素的电磁干扰,同时电子设备的小型化使干扰源与敏感单元距离越来越小,干扰传播路径缩短,干扰机会增大,干扰形式多样,而其中电磁干扰源种类多样是引起干扰影响的核心因素。为了提高电子设备、仪表的工作性能等指标,针对电源、暂态过程、电磁辐射几种常见干扰源从他的干扰因素和特点出发,采用滤波器、加静电屏蔽、吸收、电磁屏蔽等措施抑制干扰源的影响。在应用中可根据实际需要进行选择。     

提高产品质量,精心进行电磁兼容设计

任何一个电子产品都不可避免地存在一个或若干个波形产生器．时钟振荡源或高速数据传输电路．目前大多数电子设备都配备了计算机系统，因而也就有可能造成不希望的电磁辐射或电磁干扰，给人们的健康造成危害或对电子设备的正常工作造成影响。国内及国际对此都非常重视，颁布了若干个限制电子产品电磁辐射的标准及规定，如我国的3C强制认证．欧盟的CE认证．都对电子产品的额外电磁辐射作出了明确的限制和规定。     

Measurement procedures for electromagnetic compatibility assessmentof electroexplosive devices

Electroexplosive devices (EEDs) are electrically fired explosive initiators used in a wide variety of applications. A new and rigorous approach for characterizing EED firing levels is developed in the context of statistical linear models and is demonstrated. The authors combine statistical theory and methodology with thermodynamic modeling to determine the probability that an EED of a particular type fires when excited by a pulse of a given width and amplitude. Methods for assessing model validity and for obtaining probability plots, called firing likelihood plots (FLPs), are included. The results provide information that is crucial for evaluating the effects of currents induced by impulsive electromagnetic fields of short duration relative to the thermal time constant of an EED. Methods of measuring the thermal time constant of an EED and the energy needed to fire an EED with a single current impulse are given. These parameters are necessary not only to determine suitable ranges in the design of the statistical experiment, but also to assess the effect of pulses on EED's in EMC analyses     

开关电源的电磁兼容设计

近年来,电磁兼容技术已成为现代电子系统工程设计中的重要组成部分。开关电源是电子系统中主要干扰源之一,如何提高它的电磁兼容性问题显得越来越突出。本文主要从几个方面讨论了开关电源电磁兼容设计要注意的问题。     

关于印制电路板的电磁兼容设计分析

时代的发展伴随着经济的不断创新,特别是在电子行业方面,各类科技的运用也让行业的发展进入到新的篇章。在电子产品中,印制电路板是连接电子元件的主要,在电子产品中占有主导地位,其可以直接与电子产品的好坏相关联。PCB的密度随着电子产品的增多也相对增加,想要电子电路达到最好,良好的电磁兼容设计是很重要的,本文以电磁兼容为主体展开论述。     

浅谈DSP系统中的电磁兼容问题

介绍了数字信号处理系统中的干扰来源及其危害：从硬件构成、软件设计及EDA工具辅助设计三个方面详细地描述了抗干扰的方法，以使DSP系统达到电磁兼容的目的；说明了电磁兼容在电气、电子系统中的重要性。     

脉冲雷达发射机的电磁兼容设计

从电讯设计、结构工艺设计等方面分析了脉冲雷达发射机的电磁兼容性设计思路与方法。