飞机研制生产中抑制电磁干扰的探讨

通过对飞机电磁干扰产生的途径和方式进行了分析,结合飞机生产过程中排除电磁干扰的经验,对在飞机研制生产过程中有效抑制电磁干扰的方法进行了初步的探讨。     

电磁干扰产生的飞机电气系统瞬变及抑制

阐述了电磁瞬变对飞机电气系统的干扰；分析了电磁干扰的传播途径；提出了一种电磁兼容性的设计；并给出了防止电磁干扰的方法。     

辐射电磁环境干扰研究

通过对近年来飞机设计过程中出现的电磁干扰事例的回顾，以及干扰形成机理分析，提出应该注意的问题和措施。     

飞机站电磁兼容性初步研究

本文就飞机站的电磁兼容性（ＥＭＣ）问题进行了初步的分析讨论，讨论的内容主要包括：飞机站电磁干扰的控制措施，系统ＥＭＣ预测分析，系统ＥＭＣ测试等。     

某机载短波干扰飞机控制系统机理研究

文中以系统级电磁干扰测试试验为基础,利用HFSS软件对短波发射时飞机典型位置场强分布、短波馈线电流分布等进行数值仿真。最终定义了机载短波干扰飞机控制系统的机理,并为后续的解决措施的提出及验证提供了理论支持。这种分析电磁干扰机理的方法对实际工程有很大的参考价值。     

收音机接地技术研究

接地是抑制电磁干扰的主要措施之一，本文介绍了飞机上电子设备和电缆屏蔽层的接地方式，并分析了正确选择接地点的重要意义。     

某飞机火控系统电磁干扰的解决方法

本文介绍了机载系统电磁干扰产生的机理、形成条件及预防电磁干扰的措施,并以某飞机火控系统对电台干扰为例,给出电磁干扰问题的解决办法,以供相关技术人员借鉴。     

机载天线电磁耦合分析

论述如何利用电磁干扰分析表格预测两机载天线间的电磁耦合能量，并提出了减小电磁耦合的措施以及飞机天线耦合的验证方法 。     

电磁场对飞机电缆耦合的预测

本文分析了电磁场对飞机电缆的耦合途径,介绍了电磁耦合的数学计算公式,并通过实例具体地说明电磁干扰加固的调整方法。     

地阻抗与电磁干扰

飞机上各电子设备之间的传导干扰，主要是通过公共地阻抗的耦合而产生的，本文分析了接地面阻抗的大小对电磁干扰的影响，并提出降低地回路干扰的较为简便且十分有效的措施。     

某型飞机115VAC/400Hz电源干扰机通耳机的故障诊断分析

从电磁干扰三要素的角度,采用频谱分析仪法对某型飞机115VAC/400Hz电源干扰机内通话器耳机的故障进行诊断、分析,提出了抑制干扰的指导性建议。     

基于CST软件仿真的线束隔离研究

在民用飞机电气线路互联系统(EWIS)设计中,通过物理隔离防止电弧和电磁干扰(EMI)是适航审定的重要内容。以隔离距离为研究对象,基于电磁仿真软件CST,构建多种模型,对不同类型线缆间、不同电信号线路进行了仿真,证明了物理隔离不但是防止电弧产生的有效方式,而且能够极大地降低电磁干扰,同时使用屏蔽线缆和多芯扭绞等防护方法,也是降低电磁干扰的有效措施。     

Tailoring MIL-STD-461B for Naval Avionics Applications

Naval aviation electronics (Avionics) systems are specified and procured using MIL-STD-461 to set the fundamental EMI requirements. MIL-STD-461 permits and encourages ``tailoring' the EMI specifications for each equipment to the anticipated usage. In this paper, the Naval Avionics Center Staff Engineer for Electromagnetic Effects presents a typical tailored EMI specification as used within the Naval Air Systems Command to procure carrier based aircraft avionics. Included are the rationale for and the explanation of each modification and an estimate of the electromagnetic environment found aboard the US Navy Aircraft carriers.     

高铁弓网电弧对飞机进近着陆的电磁干扰影响

为了研究高铁弓网离线电弧对飞机进近着陆的电磁干扰（EMI）影响,选取高速铁路弓网离线现象发生频繁的电分相处,对高速铁路列车发生弓网离线电弧时的电磁辐射强度进行了实际测试。根据电波传播理论和GB 6364-2013的相关要求,数值计算得到了高铁下穿角、电分相位置以及飞机着陆高度对机载接收信号的影响规律：机载接收信号信干比（SIR）随着高铁下穿角增大逐渐增大;电分相距离机场跑道口越近机载接收信号的信干比越小;随着飞机进近着陆高度的减小,机载接收信号信干比先减小后增大。以高速铁路45°角下穿机场跑道中心时,以飞机受干扰最强的位置分析了弓网离线电弧电磁干扰对仪表着陆系统（ILS）信标台的影响：飞机接收到的航向信标台信号信干比为12.92 dB,小于GB 6364-2013规定最小20 dB的防护率要求;下滑信标台信号信干比为29.08 dB,符合国标要求;指点信标台信号信干比为16.64 dB,小于国标规定的最低23 dB的防护率要求。本文研究为民航与高速铁路的电磁兼容性研究提供了理论依据和技术方法,可以为机场选址和高速铁路选线规划提供支持。     

A fiber-optic current sensor for aerospace applications

A robust, accurate, broadband, AC sensor using fiber optics that is being developed for space applications at power frequencies as high as 20 kHz is described. It can also be used in low- and high-voltage 60-Hz terrestrial power systems and in 400-Hz aircraft systems. It is intrinsically immune to electromagnetic interference (EMI) and has the added benefit of excellent isolation. The sensor uses the Faraday effect in optical fiber and standard polarimetric measurements to sense electrical current. The primary component of the sensor is a specially treated coil of single-mode optical fiber, through which the current-carrying conductor passes. Improved precision is accomplished by temperature compensation by means of signals from a novel fiber-optic temperature sensor embedded in the sensing head. The technology used in the sensor is discussed, and the results of precision tests conducted at various temperatures within the wide operating range as well as the results of early EMI tests are reported     

Optical fiber wavelength division multiplexing

During flight, aircraft avionics transmit and receive RF signals to/from antennas over coaxial cables. As the density and complexity of onboard avionics increases, the electromagnetic interference (EMI) environment degrades proportionately, leading to decreasing signal-to-noise ratios (SNRs) and potential safety concerns. The coaxial cables are inherently lossy, limiting the RF signal bandwidth while adding considerable weight. To overcome these limitations, we have investigated a fiber optic communications link for aircraft that utilizes wavelength division multiplexing (WDM) to support the simultaneous transmission of multiple signals (including RF) over a single optical fiber. Optical fiber has many advantages over coaxial cable, particularly lower loss, greater bandwidth, and immunity to EMI. In this paper, we demonstrate that WDM can be successfully used to transmit multiple RF signals over a single optical fiber with no appreciable signal degradation. We investigate the transmission of FM and AM analog modulated signals, as well as FSK digital modulated signals, over a fiber optic link (FOL) employing WDM. We present measurements of power loss, delay, SNR, carrier-to-noise ratio (CNR), total harmonic distortion (THD), and bit error rate (BER). Our experimental results indicate that WDM is a fiber optic technology suitable for avionics applications.     

EMI滤波器控制传导干扰实验与分析

应用理论分析和实验总结出来的关于共模和差模传导干扰信号的分布规律,分析电子设备电源线上存在的干扰信号的特点,试用不同网络结构的电磁干扰(EMI)滤波器来控制电子设备在在的传导干扰电平,使之符合有关电磁兼容性(EMC)标准规定的极限值为例,说明EMI滤波器设计和应用中碰到的某些实际问题,对指导用EMI滤波器来解决电子设备存在的电磁干扰和进行EMC试验很有实际意义。     

A new resonant link aircraft power generating system

A 400 Hz aircraft power generating system which has been designed to achieve significant improvements in power density and reliability is introduced. Design targets for this exploratory development program include system (generator-plus-converter) power density of 1 kVA/lb and mean-time-between-failure (MTBF) of 500 h. At the heart of the new variable-speed constant-frequency (VSCF) configuration is a high-frequency resonant link inverter designed so that all inverter switching occurs under zero-voltage conditions. Advantages include minimization of switching losses and significant reductions in power device switching stresses and electromagnetic interference (EMI) generation. Inverter losses are further reduced by using MOS-controlled thyristors (MCTs) as the power switches in order to take advantage of their low forward voltage. A 60 kVA breadboard version of the system has been constructed, and test results which confirm its key performance characteristics are presented     

高频PCB中EMI问题的研究

高频PEB中的EMI使得一些敏感电路、集成块的工作性能有所降低，甚至不能工作。在研究电路板中存在的电磁现象后，分析了PCB在布局、布线、滤波等方面产生EMI原因，并针对这些问题提出减小电流、降低速度、增加磁性元件等新颖的解决办法，并且在实际PEB制作中用取得了很好的效果，降低了EMI的强度。抗EMI的效果是要通过测试才能更好了解，EMI测试是必不可少的环节。     

民用飞机地面漂浮性分析研究及应用

民用飞机地面漂浮性是评估飞机-机场相容性的一个重要指标,其直接影响到飞机设计参数选择以及地面适应性的优劣。在总体概念设计阶段就必须对飞机的漂浮性能进行分析评估,从而选择恰当的飞机参数。对民用飞机在刚性道面和柔性道面上漂浮性分析方法做了简要说明,并针对国际民用航空组织所推广使用的ACN/PCN(飞机分类号/机场分类号)方法进行了详细分析研究,在此基础上,开发出了飞机地面漂浮性分析软件。通过直接输入飞机相关参数可以快速准确地计算出飞机分类号ACN值。可以有效地对飞机地面漂浮性进行评估和优化,从而解决了用手工方式评估飞机地面漂浮性时的繁琐及不准确,并降低了对从事飞机地面漂浮性计算的人员要求。