发动机油底壳辐射噪声预测方法的研究

介绍了对发动机油底壳进行噪声预测的两种方法。通过振动速度法,估算了油底壳辐射的声功率级。用FEM／BEM方法进行预测时,考虑了油底壳中润滑油的耦合作用,并对耦合情况与非耦合情况的计算结果进行了比较,表明耦合作用对油底壳的振动有较大影响,并与声强法测量的油底壳左右两侧的声强图进行了比较,声强分布基本一致。结论：FEM／BEM方法是预测发动机油底壳辐射噪声的有效方法。     

混响室校准及测试

本文首先对混响室的发展、原理、主要性能参数进行了介绍,在此基础上依据标准IEC 61000-4-21中的规定,对混响室的校准方式进行了详细介绍和分析,并以辐射电磁场抗扰度为例,具体说明在混响室内进行测试的方法步骤.     

开发通用的射频电磁场辐射抗扰度自动测试软件

本文介绍了作者开发的通用射频电磁场辐射抗扰度自动测试软件的设计思路、实现方法及其主要功能特点.开发该软件的出发点在于通用性,即实现对不同品牌、多种类型的用于射频电磁场辐射抗扰度测试的测量仪器的控制,并协调完成射频电磁场辐射抗扰度的自动测试.本文就如何实现软件的通用性,阐述了作者的设计思路和实现方法.另外,还详细介绍了最终软件产品的特点.     

气门淬火层深一致性差原因分析一例

本文通过一款轻型客车进气系统噪声优化设计的案例,详细介绍了轻型客车进气系统气动噪声、结构辐射噪声的优化过程和分析方法。提出了一些进气系统设计过程中需要关注的方向,对进气系统的噪声控制和结构改进具有一定的指导作用。     

推行“在线检测”试点班组纪实

本文通过一款轻型客车进气系统噪声优化设计的案例,详细介绍了轻型客车进气系统气动噪声、结构辐射噪声的优化过程和分析方法,提出了一些进气系统设计过程中需要关注的方向,对进气系统的噪声控制和结构改进具有一定的指导作用。     

辐射骚扰试验测量不确定度的评定

提出对辐射骚扰试验水平极化和垂直极化测量结果分别进行不确定度评定的方法,并以电能表为受试设备进行评定,评定的结果优于相应标准的要求,表明该试验系统的测量结果是可信的、可靠豹.     

利用扩频技术减少高速时钟电路的电磁干扰

数字电子设备的运行速度越来越快,其时钟频率就越来越高,时钟电路产生的辐射干扰就越为严重。本文介绍了一种对抑制时钟电路辐射干扰较为有效的方法-时钟扩频技术。     

Radiated noise analysis via human body for intra-body communication

The transmission path of intra-body communication is composed of capacitance coupling among nodes. Therefore, a channel model of the communication is expressed by capacitive ambient elements. Such a communication is greatly affected by external noise because the balance of the transmission path deteriorates due to environmental factors. There is a serious problem in that radiated noise via the human body emitted from an electric light or peripheral electronic equipment is likely to be transmitted along the same path as a signal by capacitance coupling. We investigated a channel model and estimated radiated noise via the human body based on experiments and circuit simulation. The validity of the channel model was clarified from noise measurement. When an additional electrode was connected to a ground electrode in a measurement system for a practical scene, the noise reduction rating was 5.11 dB. However, actually, reducing the noise is difficult. Therefore, reducing the noise source in such a communication is necessary.     

Investigation of electromagnetic radiation induced by conducting wire of nanometer multi-quantum well device on InGaN LED

It is known that electromagnetic interference (EMI) has a negative effect upon the performance of electronic communication systems. The present study considers the case, where EMI is induced in an conducting wire (CW), and derives equations to establish the influence of the induced EMI on InGaN material of nanometer quantum well light-emitting diodes (LED). These equations are then verified experimentally. The present results indicate that the degree of influence of the EMI upon the InGaN LED device depends upon the interference power, the interference frequency, the induced power, the input resistance of the device, the inverse saturation currents, and the ideal factor of the LED. Moreover, the greater EMI amplitude and frequency, the greater deterioration I-V curves of the InGaN LED.     

混响室条件下线缆共模干扰临界辐射干扰场强测试研究

为在混响室中线缆共模干扰时的设备(EUT)进行临界辐射干扰场强测试,并确保与开阔场中测试结果一致,该文推导了线缆上共模电流满足的方程,将共模电流分解为相应的特征电流,计算了终端负载任意时线缆最大方向性系数的变化范围。以单导体传输线和同轴线为EUT,分别在混响室和开阔场中测试线缆的临界干扰场强,对计算结果进行了验证。结果表明：最大方向性系数的计算结果可以保证两种不同场地中测试结果的一致性,双线的共模干扰以及同轴线均可以等效为单线,且线缆弯曲对测试结果基本没有影响。