卫星通信天线控制系统中的抗干扰问题

结合由可编程逻辑控制器(PLC)及变频器组成的卫星通信天线控制系统在应用中的抗干扰问题,介绍了PLC及变频器的工作特点,分析了控制系统中干扰产生的原因,结合实际工程应用从抑制干扰源、切断或衰减电磁干扰的传播途径以及提高系统的抗干扰能力出发,提出了几个有效的抗干扰措施,包括电源的处理及选择、电缆的选择、对布线的要求、硬件设计和软件滤波、正确选择接地点等.     

变频器电磁干扰及防治措施

随着工业自动化程度的不断提高,变频器得到了非常广泛的应用,同时变频器带来的干扰问题也逐渐突出,影响到系统的稳定运行。根据变频器工作原理,分析变频器使用过程中电磁干扰产生原因及其传播途径,此外提出防治电磁干扰的具体措施,给出变频器应用系统设计和现场安装时的注意事项。     

变频器应用中抗干扰问题的探讨

变频器在工业生产中的应用越来越广泛,其干扰问题日益引起人们的重视。本文主要讨论变频器应用系统中干扰产生的来源及其传播途径,提出了抗干扰的实际解决方法,阐述了在变频器应用系统设计和安装中抑制干扰的具体措施。     

变频器应用系统电磁干扰分析及其抑制

在变频器调速系统的实际应用中,为了防止电磁干扰对变频器造成危害,必需采取抗干扰措施。本文对变频器电磁干扰的重要来源谐波干扰的产生进行分析,并介绍了抗干扰的几种措施,为变频器电磁兼容性和电磁环境分析提供了依据。     

矿用变频器干扰问题及解决对策

本文介绍了矿用变频器产生干扰的原因、干扰类型和传播途径,并提出了相应的抗干扰解决对策。     

钢铁企业中工控系统的抗干扰问题分析

在钢铁企业中无论是炼铁、炼钢、轧钢还是其他辅助生产线，都大量使用变频器。而变频器运行时既要防止外界干扰它，又要防止它干扰外界，变频器干扰再加上别的电磁干扰，给工控系统正常运行带来了麻烦。文中分析了电磁干扰及其对工控系统干扰的机制，指出在工程应用时必须综合考虑工控系统的抗干扰性能，并结合工程提出了几种有效的抗干扰措施。     

变频器系统电磁干扰故障分析

本文通过对电磁干扰的主要传播途径的介绍及对电磁传导干扰的产生机理的分析提出了抑制电磁干扰的措施,并以工程实例介绍了分析变频器系统电磁干扰故障现象及排除过程,指出了在变频器系统设计、制造和安装施工中应充分考虑电磁兼容性的重要性。     

矿用变频器的EMC解决方案

为促进变频调速系统在煤矿领域的进一步发展,针对现在阶段我国煤矿变频器使用的电磁环境,分析了矿用变频器运行中产生和受到各种电磁干扰及传播途径,并结合实际使用情况提出变频抗干扰的实际解决方法,阐述了煤矿井下变频调速系统在设计和安装过程中具体的抑制干扰措施.实际结果表明,变频调速系统成功应用于井下采掘设备,工作面其它设备及传感器运转正常,取得了较好的经济效益及社会效益.     

信号系统中变频器的干扰分析与抑制

针对变频器工作过程中对信号系统产生严重干扰的现象,分析了变频器电磁干扰产生的机理,总结了变频器干扰的抑制方法,最后在信号系统抗干扰实验中验证了干扰抑制方法的效果。     

变频控制系统电磁干扰分析及对策

针对某水厂变频控制系统中存在的电磁干扰问题，在分析控制系统结构及电磁干扰产生的原因和传播途径的基础上，给出了抗干扰措施。经过抗干扰处理后，该变频控制系统通讯正常，误动作消除。     

电子整流与逆变系统中电磁干扰分析

针对电子整流与逆变系统设计应用中的电磁干扰问题,详细介绍了电磁干扰特性以及常用电路的电磁兼容方法,通过对整流与逆变系统的干扰测试,提出了已经生产的产品形成干扰的抑制方法.测试结果表明该方法能够极大的减小系统中的电磁干扰.     

变频调速系统干扰的抑制措施及分析

在变频器传动电动机系统中,变频器与电网、变频器与电动机以及周边设备相互之间都存在着干扰,安装时应采取适当的抗干扰措施,要实现变频器都能安全可靠的运行,必须对相互干扰采取抑制措施。     

变频器干扰抑制技术探讨

本文介绍并分析了变频器本身和外部EMI的来源,根据EMI产生的三要素原理,重点从硬件和软件两方面对比分析了变频器EMI的抑制措施。最后对各种方法,需要注意的问题以及未来变频器EMI抑制的发展方向进行了总结和展望。     

Joint multi-cost routing and power control in wireless ad hoc networks

In this work we study the combination of multi-cost routing and adjustable transmission power in wireless ad hoc networks, so as to obtain dynamic energy- and interference-efficient routes to optimize network performance. In multi-cost routing, a vector of cost parameters is assigned to each network link, from which the cost vectors of candidate paths are calculated. Only at the end these parameters are combined in various optimization functions, corresponding to different routing algorithms, for selecting the optimal path. The multi-cost routing problem is a generalization of the multi-constrained problem, where no constraints exist, and is also significantly more powerful than single-cost routing. Since energy is an important limitation of wireless communications, the cost parameters considered are the number of hops, the interference caused, the residual energy and the transmission power of the nodes on the path; other parameters could also be included, as desired. We assume that nodes can use power control to adjust their transmission power to the desired level. The experiments conducted show that the combination of multi-cost routing and adjustable transmission power can lead to reduced interference and energy consumption, improving network performance and lifetime.     

Orthogonal Cochannel Operation for High Spectrum Efficiency Based on the Example of 16 QAM-140 Mbit/s Systems Using Rolloff 0.19

In view of the rapidly increasing demands for transmission capacity of public networks and the limited number of radio frequencies available, the band efficiency of existing systems in general will become insufficient for future high-capacity requirements. This fact is becoming increasingly evident for 16 QAM-140 Mbit/s radio systerns at 3.9, 6.7, and 11.2 GHz which are in widespread use in todays long-haul transmission networks. Conceptual and technological measures for making cochannel operation feasible and practical are presented using the example of a system family. By these means, even the capacity of existing 16 QAM-140 Mbit/s radio routes with 40 MHz interleaved channel arrangements can be doubled with the particular advantage of reutilizing the existing antennas and radio equipment with only minor modifications. A progressive filter concept makes orthogonal cochannel transmission possible with negligible adjacent channel spectrum interference. Surface acoustic wave IF filters are used to convert existing systems from 0.5 rolloff to 0.19 rolloff. Special RF channel/antenna arrangements were developed for the transmission of all RF channels in both directions, including space diversity and using only two antennas. A field experiment verified the feasibility of the concept and indicated that a crosspolar interference canceller is generally not necessary for 16 QAM140 Mbit/s cochannel operation.     

过境卫星对广电专用卫星的干扰及应对措施

作为广播电视信号三大传输手段之一的卫星传输技术,在当前仍然扮演着重要角色。卫星传输系统是一个开放系统,易受到外界信号的干扰。过境卫星干扰由于其具有隐蔽性、特殊性,给广播电视卫星传输带来许多不利影响。本文结合工作实际,通过介绍近年来发生的干扰实例,对过境卫星干扰的机理进行分析,提出减小干扰的有效措施,为同行提供一定的借鉴作用。     

Beam interference suppression in multi-cell millimeter wave communications

Due to the increase in the number of users, beam switching is used for suppressing interference, which leads to higher computational complexity in multi-cell millimeter wave communications. In order to resolve this problem, a beam interference model is introduced, and a lower complexity beam interference suppression algorithm based on user grouping is proposed. The proposed algorithm operates beam switching and multi-cell cooperative transmission for a part of the users when there exists beam interference due to high user density. In particular, considering the distinct interference suffered by each user, the proposed dual-threshold user grouping method can effectively solve the frequent switching problem at the base station caused by multi-cell cooperative transmission in multi-cell environments. Simulation results show that the proposed algorithm can reduce the computational complexity of beam switching and approach ideal system capacity, compared with conventional interference suppression algorithms that do not involve grouping of users.