1、电磁干扰对通信和电子系统的破坏性影响英文翻译电磁干扰对通信和电子系统的破坏性影响英文翻译电磁干扰对通信和电子系统的破坏性影响 电子与电磁干扰 电的存在促成了电气和电磁噪声以及电磁干扰的周围区域。 对电磁传输系统在信息技术应用方面的使用的日益增加的需求和依赖，使革命性的通讯能力包括了无线通信设备，无线网络，和卫星通信系统。这些系统在部分电磁波谱中运作，而随着这些设备的增加，电磁辐射在这部分电磁波谱中也有一定的增强。这些放射物有可能会干扰正常的电子通讯联系和系统的运作和功能。 电磁能量干扰电子设备正常运行和功能的情况被称为电子干扰（EI）。EI的来源可以分为环境的（自然发生的） ，偶然的/伴随的/
2、附带的或故意的。EI的影响可能会很大，这与其来源无关，然而与工程设计和其他可以用来限制EI对电子，通信和信息系统的影响和破坏的因素有关。 电磁干扰（ EMI ） 电力和电磁干扰的基本概念包括一个发射源和一个受影响的装置或系统。能量在系统之间的转移可以通过辐射、传导或电磁感应产生。通过传输路径、导电路径或通过磁耦合可以分别促进能量的实际转移。 影响到无线通讯联系的干扰，通常是由通过辐射或传导产生的能量转移造成的。导电性影响的状态，就会发生在信号被一个连接到受影响系统上的行动导体接受时候。 电磁干扰（ EMI ）的来源大致可分为下列几类： 附带干扰 外部噪声 互调失真 杂散发射 邻道干扰 环境干扰
3、 带拥塞 蓄意干扰 电子系统在存在干扰的情况下进行可靠运行的能力，被称为电磁兼容性（ EMC ） 。有几种方法可以使电磁干扰从干扰源向受影响系统转移：辐射、传导和电磁感应。 附带干扰 设备无法区分期望信号，是由于接收了一个强有力的不是期望信号的信号。这往往是由与电路设计，可能导致无法拒绝这些不受欢迎信号的屏蔽要求和与期望信号相关的带外管理有关的问题引起的。 电子设备的运作造成了不同层面电磁辐射的放射物。这些设备包括无线设备，移动电话和雷达系统。附带的EI对医疗器械和飞机电子设备有着重要影响，在这些不能电磁兼容的设备之间的干扰可能会造成潜在破坏性影响。 9 外部噪声 外部噪声源可能具有电磁或电子
4、的性质。电磁源噪声可以有不同的强度和周期，而电子源噪声在性质上是不变的。 杂散发射 一个收发器的明频段以外的信号的传输被认为是杂散发射，也可以成为离散窄带或宽带噪声信号的形式。一个杂散发射的发生包括频率是基本频率倍数的谐波。 邻道干扰 造成邻道干扰的原因可能是在与选定信号频率相对接近的频度收到了一个强有力的信号。邻道干扰通常可以通过使用适当的发射器和接收器的设计技术，最大限度地减少。 带拥塞 除了调制技术、发射器和接收器设计还有频带过于拥挤，可能会造成在共享或密集频带中运行的设备之间的严重干扰。 环境干扰 在我们生活的环境中有天然的电磁辐射源。 这些环境辐射放射物可能会干扰电子系统和通信数据链
5、的运作和成效。闪电和太阳能都是电子干扰的环境来源的实例。 蓄意干扰（无线电干扰） 能量的蓄意发射对另一个设备或电子系统造成的噪音或干扰，被称为“蓄意干扰（无线电干扰）”。 对电子或通信系统的蓄意破坏是一个课题，这一课题必须在数据通信链的设计中被考虑，尤其在更加依赖无线通讯技术作为关键系统的主要传播媒介的情况下。一种被称为人为干扰的技术是蓄意电子干扰的一个实例。这种状态是通过蓄意放射或电磁能量反射或为了破坏另一个系统的电磁信号的信号造成的。这种技术可以用于电磁波谱的窄带或宽带部分。有效地堵塞一个信号或聚集一组信号，通常需要使用高功率发射机，它可以发射强于目标信号的信号。接收器的易感性在大量的传输
6、力中，也是一个重要因素，这一传输力对有效地堵塞或中断通信联系或系统是必须的。 蓄意干扰有能力破坏无线电通信，雷达和无线电导航系统。在足够水平的某一特定频率或频段上的RI能量传输可以基本上压倒或显着减少信号的完整性。 另外的传播电磁波通过大气传播。 多路径原始信号的多个副本时被接收的情况。这些多重信号具有不同的振幅和相位的变化，这可以看作是对一个接受器的干扰。 反射信号反映信号路径上的物体的结果。影响卫星信号的因素 另外的影响无线通讯联系整体可靠性的信号传播因素包括： 电离层衰减 对流层衰减 调制技术用于无线传输系统对无线传输系统的整体性能和对特定类型的噪音和干扰的易感性有重大影响。有不同的调制
7、技术，它们可以提供优越的抗噪声性能，也因此提供了更好的系统性能。 电磁干扰对策 有一些可能的对策可以对付电子和通讯系统干扰的影响。如果干扰结合了多种来源，那么纠正行动就可能非常复杂。以下是一些对付电磁干扰的影响技术： 消除干扰源 一个有效的消除干扰的技术是查明和消除干扰源。从理论上讲，这是无疑是最有效的措施，但在很多情况下是不现实的，因为这要求干扰源是定期或终身不运作的。 接地 接地是指向一个设备或多个设备的共同参照点，这有确保设备和运作者安全的功能，还可以提供一些抗噪音和抗干扰因素。某些传输和其他电子设备需要足够的接地，以确保正常运行。用于设备地面的导体应该是最短的，这样可以避免接地回路状态
8、。这可能导致能量通过传导转移到所连接的设备。 过滤器 使用过滤器可以使所选择的频率通过的连接设备，而拒绝或减少任何过滤器规格以外的其他频率通过。过滤器的例子包括低通，带通和高通。 屏蔽 减少或在某些情况下消除电磁干扰的有效方法是，是有效地屏蔽组件相互作用。这种技术通常花费是很高的，会导致主要的设计工程挑战，尤其是充分屏蔽一个装置，这就要求设备或电路完全附上导电材料。屏蔽材料的任何分离都会降低屏蔽技术的效力。 Disruptive Effects of Electromagnetic Interference on Communication and Electronic Systems Ele
9、ctronic and Electromagnetic Interference The presence of electrical contributes to the surrounding levels of electrical and electro-magnetic noise and interference. The increasing demand and dependence on The use of electromagnetic transmission systems for information technology applications has ena
10、bled revolutionary communications capabilities to include cordless communication devices, wireless networking, and satellite communication systems. As the number of these devices increases, there is an increase in electromagnetic radiation within the segments of the electromagnetic spectrum in which
11、 these systems operate. These emissions have the potential to interfere with the normal operation and function of electronic communication links and systems. The condition of electromagnetic energy disrupting the normal operation or function of electronic devices is known as electronic interference
12、(EI). The source of EI can be categorized as environmental (naturally occurring), incidental or intentional. The effects of EI can be significant regardless of their source, however, engineering design and other considerations that can be used to limit the impact and disruption of EI on electronic,
13、communication and information systems. Electromagnetic Interference (EMI) The fundamental concept of electrical and electromagnetic interference involves an emanating source and an affected device or system. The transfer of energy between systems can occur through radiation, conduction, or induction
14、. The actual transfer of energy is facilitated respectively through a transmission path, conductive path, or through magnetic coupling. The interference that affects wireless communication links is typically the result of radiated or conductive energy transfer. The condition of a conductive affect o
15、ccurs when the signal is picked-up by a conductor attached to the affected system. The sources of EMI can be generally separated into the following categories: Incidental interference External noise Intermodulation distortion Spurious Emissions Adjacent Channel Interference Environmental Interferenc
16、e Band Congestion Intentional Interference (Jamming The ability of electronic systems to operate reliably in the presence of interference is known as electromagnetic compatibility (EMC). There are several ways that EMI can transfer from a source to the victim: radiation, conduction, and induction. I
17、ncidental Interference The situation when a device is unable to distinguish a desired signal due to the reception of a strong signal which is not the desired signal. This can often be the result of issues relating to the circuit design, shielding requirements which can lead to the inability to rejec
18、t these unwanted signals that occur within and out-of-band in relation to the desired signal. Incidental Interference The operation of electronic devices causes the emission of electromagnetic radiation of different levels. These devices include wireless devices, mobile phones and radar systems. Inc
19、idental EI is a major concern with both medical devices and airplane electronics, where interference between devices that are not electromagnetically compatible with each other can have potentially devastating effects. 9 External Noise External noise sources can be electromagnetic or electrical in n
20、ature. Noise from electromagnetic sources can vary in their intensity and period, whereas electrical sources are constant in nature. Spurious Emissions The transmission of signals that are outside the prescribed frequency band of a transceiver are considered spurious emissions and can be in the form
21、 of discrete narrowband signals or wideband noise. One common occurrence of spurious emissions involves harmonics at multiples of the fundamental frequency. Adjacent Channel Interference Adjacent channel interference may be caused by receiving a strong signal at a relatively close frequency to the s
22、elected signal and can often be minimized through the use of proper transmitter and receiver design techniques. Band Congestion The overcrowding of frequency bands in addition to modulation techniques, transmitter design and receiver design can cause significant interference between devices operatin
23、g within shared or closely spaced frequency bands. Environmental Interference The environment in which we live has natural sources of electromagnetic radiation. These environmental radiation emissions can interfere with the operation and effectiveness of electronic systems and communication data lin
24、ks. Examples of environmental sources of EI are lightning and solar energy. Intentional Interference (Jamming) The intentional emanation of energy to cause noise or interference to another device or electronic system is known as jamming. The effectiveness of conducting this type of activity depends
25、on numerous The intentional disruption of electronic or communication systems is a topic that must be considered in data communication link design, especially with the increased reliance on wireless communication technology as the primary communication medium for critical systems. A practical exampl
26、e of intentional EI is a technique known as jamming. This condition is the created through the intentional emission or reflection of electromagnetic energy or signals for the purpose of disrupting the electromagnetic signals of another system. This technique can be employed for a narrow band or wide
27、 band portions of the electromagnetic spectrum. The ability to effectively jam a signal or group of signals typically requires the use of a high-power transmitter which produces a signal that is stronger than the target signal. The susceptibility of the receiver is also an important factor in the am
28、ount of transmission power necessary to effectively jam or disrupt a communication link or system. Intentional interference has the capability of disrupting radio communications, radar and radio navigation systems. The transmission of RF energy at a specific frequency or frequency band of sufficient
29、 levels can essentially overpower or cause significantly reduced signal integrity Additional Propagation Affects The propagation of electromagnetic waves through the atmosphere Multipath - The condition when multiple copies of an original signal are received. These multiple signals have different am
30、plitude and phase variations which can appear as interference to a receiver. Reflection The result of a signals reflecting from objects in the signal path. Factors Affecting Satellite Signals There are additional signal propagation factors that affect the performance and overall reliability of a wir
31、eless communication link, which includes: Ionospheric Attenuation Tropospheric Attenuation The modulation technique used for a wireless transmission system can have a significant affect on the overall performance of a wireless transmission system and its susceptibility to certain types of noise and
32、interference. There are different modulation techniques that offer superior noise immunity and as a result offer improved system performance. EMI Countermeasures There are a number of possible countermeasures to counter the effects of interference with electronic and communication systems. The corrective action may be very complex if the interference is a combination of multiple sources. The following are some of the tech
