一种辐射发射近场测试系统方案的设计与优化

辐射发射(RE)的设计和远场测试整改复杂、成本高,为了解决中小规模公司缺乏低成本、简单的近场摸底测试系统的问题,设计验证了一种基于数字示波器的近场辐射发射测试系统,可用于获取远场RE102测试的频谱走向和趋势,使产品的EMI认证成本减少1/3,试验周期缩短1/5.为远场测试整改难度大、成本高的问题提供了一种解决方案.     

电动汽车充电桩电磁兼容测试现状及分析

分析了电动汽车充电桩/机电磁兼容测试的相关测试标准、测试方法及结果,指出当前存在的标准跟进不及时、测试方法和判据不统一、测试通过率较低、整改不确定度较大等问题,并提出自己的分析和看法。     

电动汽车电磁辐射干扰整改

某款电动汽车样车依据GB/T 18387测试时,电磁辐射超标。分析了该车的整车电磁辐射骚扰特性,并制定了在动力线束上安装滤波器、加强壳体屏蔽、增大动力线束屏蔽层密度等整改方案。整改后,样车电磁辐射测试结果符合标准要求。     

电动汽车交流充电传导干扰的排查整改

随着GB/T 40428-2021逐步成为公告法规类测试项目,各车企也加大了研发测试频率和投入,其中的交流充电传导发射测试是该项目测试的一个难点。文章分享了一个纯电动汽车传导干扰整改案例,通过排查定位、可工程化整改、以及回归验证等步骤,解决了该试验车辆的传导发射超标问题,最后总结了一个交流充电传导干扰排查整改工程化方案的确定流程,供行业各位专家参考。     

医用光学定位系统辐射发射整改措施分析

针对某光学定位系统辐射发射的超标问题,分析其干扰原因,进行干扰源的定位和超标原因分析,并从电路布局、结构设计、骚扰源滤波设计、减小接地阻抗等方面对样品进行了整改分析及整改实施。整改后,辐射发射测试结果符合GB 4824-2019中1组A类测试要求,对其他类似医疗产品进行电磁兼容设计、整改具有一定参考价值。     

基于B/S结构的信息系统后台性能测试与分析

大型信息系统因其用户规模大,业务变化快等特点更多地采用了B/S结构的多服务器集成模式,B/S结构把业务处理集中在系统后台的特性,使得高效、可靠的系统后台成为系统运作流畅的关键。本文以一个基于B/S结构的大型在运行系统性能测试为例,通过测试分析系统存在缺陷,实现了系统故障和性能问题的有效定位,对存在问题提出了可行的优化建议,系统整改效果良好。文章对数据的详尽细致分析,不仅为系统优化指明了方向,而且对系统的开发建设也具有相当的参考价值。     

电动摩托车电机控制器的辐射抗扰对策

依据GB/T 17619—1998的规定对电动摩托车控制器进行辐射抗扰度测试中,出现了控制电机转速不稳定且偏离正常值的问题。通过分析,提出了用短的皮包线重新焊接代替长环路铜线的整改方案。整改后,电动摩托车控制器工作正常。     

基于电磁兼容风险评估方法的EMC整改研究

针对电子设备EMC设计及测试整改中的困难,研究了电磁兼容风险评估方法。通过划分风险评价单元、确定风险要素及影响程度、列出风险分布矩阵、制定排查路线图等多个步骤,可以清楚地发现产品在EMC设计方面的优点、缺点与风险,为产品EMC设计整改方案提供方向。再根据排查路线图采用合理的技术措施,并结合EMC测试的结果,可实现产品快速改进并通过EMC测试。该方法对电磁兼容正向设计也有借鉴意义。     

G/T值自动化测试

G/T值是卫星地面接收系统的一项重要指标,常规测试方法耗时、费力、计算量大。通过工程实践详细论述利用射电星法测量地面大型天线系统的G/T值的原理及计算方法,论证G/T值自动化测试的可行性,并对测试过程中引入的测量误差进行了分析,给出G/T值自动化测试的实现方法及测试结果。该方法具有自动化程度高、测试指标精度高、测试速度快等特点,可广泛应用于各种卫星地面接收、航天测控等设备。     

心音心电检测仪电磁兼容问题的测试分析及整改方法

现代医疗器械更偏向于高精确度、高敏感度和小型化,其所处的电磁环境越来越复杂。外界电磁干扰对医疗设备会产生影响,严重时甚至影响医生的诊断。本文结合心音心电检测仪,基于医疗器械测试标准对传导发射测试、辐射发射测试和静电放电这3个测试项目进行了研究,提出了壳体整改,增加滤波电路、磁环、电荷释放电路等整改方法。对其他类型相关医疗器械的电磁兼容问题分析和整改,有一定的参考借鉴作用。     

手机辐射杂散问题的分析

辐射杂散问题是手机EMC设计中的常见难题。引起RSE问题的因素较多，同样的表现形式可能存在不同的根源。以GSM制式为例，分析了手机产品辐射杂散问题的形成原因，即：带外寄生发射、带内变频产物发射、不同因素导致的谐波发射超标以及开关谱引起的主频边带发射超标等，并针对不同的问题类别，提出了相应的整改建议。     

在Eclipse中使用RSE框架的探讨

传统C/S结构的远程处理程序存在高度依赖客户端,界面响应速度慢,不能充分发挥客户端性能等弱点。随着Eclipse平台和RSE框架的出现,使远程处理应用程序开发重新成为了焦点。使用基于Eclipse平台和RSE软件框架构建远程处理正在成为当前越来越多的企业采用的一种方法,这种方法快速、高效、开发团队只需要将关注点投射于领域业务逻辑即可。在此深入地分析RSE框架的体系结构,并结合实例介绍Eclipse下采用RSE开发远程处理的实现方法。该方法使软件架构更加合理,可维护性强,并且大幅缩短了开发时间,取得了良好效果。     

Effect of reactive sputter etching of SiO2 on the properties of subsequently formed MOS systems

We investigated the effects of reactive sputter etching (RSE) of SiO₂ on the electrical properties of the SiSiO₂ system using CHF₃ in a commercial apparatus. SIMS and Auger spectrometry revealed contamination of RSE-exposed Si surfaces with carbon and heavy metals. The generation of crystal defects during thermal reoxidation was observed to be closely related to the level of metal contamination. C-V, C-t and I-V measurements on subsequently formed MOS structures showed, that oxide charge, interface state and mobile ion densities are nearly unaffected by the RSE process. However, minority carrier lifetime in the Si substrate and isolation behavior of the oxide layer are strongly degraded; our results suggest, that both effects are mainly due to metallic impurities. The use of inert cathode materials like quartz reduces metal contamination, but a non-negligible contribution from the grounded metal surfaces of the reactor remains. Carrier lifetime and insulating properties reach the values obtained on wet chemically etched samples only after extended times of plasma excitation in the apparatus. This is attributed to a passivation of the grounded surfaces by the formation of polymer films. Taking advantage of this effect MOSFETs were fabricated by the use of RSE without deterioration of their electrical performance.     

Gas-Source molecular beam epitaxy and characterization of inGaAs/lnGaAsP quantum well structures on InP

In this paper, we report the effect of using a group-V residual source evacuation (RSE) time on the interfaces of InGaAs/lnGaAsP quantum wells (QWs) grown by gas-source molecular beam epitaxy. High-resolution x-ray rocking curve and low-temperature photoluminescence (PL) were used to characterize the material quality. By optimizing the RSE time, a PL line width at 15K as narrow as 6.6 meV is observed from a 2 nm wide single QW, which is as good as or better than what has been reported for this material system. Very sharp and distinct satellite peaks as well as Pendellosung fringes are observed in the x-ray rocking curves of In_xGa_1−xAs/InxGa_1−xAS_yP_1−y multiple QWs, indicating good crystalline quality, lateral uniformity, and vertical periodicity. Theoretical considerations of the PL linewidths of In_xGa_1−xAs/InxGa_1−xAS_yP_1−y single QWs show that for QW structures grown with the optimized RSE time, the PL linewidth is mainly due to alloy scattering, whereas the contribution from interface roughness is small, indicating a good interface control.     

基于Matlab/Simulink的单相触发电路的设计与实现

文中基于Matlab／Simulink设计了一个单相可控整流电路的触发电路。并阐述了触发电路的模块化与封装方法。该触发装置在Simulink环境下具有友好的用户界面，使用方便，简化了单相可控整流电路的仿真模型。通过对单相桥式整流电路的仿真，体现了该触发装置在单相可控整流电路仿真中的良好效果。     

Design of a power-factor-correction converter based on half-bridgetopology

A single-stage AC/DC converter based on a half-bridge topology suitable for low-power-level applications is proposed. The proposed converter has high power factor, low harmonic distortion, and tight output regulations. An asymmetrical control and synchronous rectification are employed to reduce the switching and rectification losses, respectively. The modeling and detailed analysis are performed to derive the design equations. Based on these design equations, a prototype converter has been designed and tested by experiment. This prototype meets the IEC 61000-3-2 regulations with near-unity power factor and high efficiency     

Design of packet-fair queuing schedulers using a RAM-basedsearching engine

The implementation of packet-fair queuing (PFQ) schedulers, which aim at approximating the generalized processor sharing (GPS) policy, is a central issue for providing multimedia services with various quality-of-service (QoS) requirements in packet-switching networks. In the PFQ scheduler, packets are usually time stamped with a value based on some algorithm and are transmitted with an increasing order of the time-stamp values. One of the most challenging issues is to search for the smallest time-stamp value among hundreds of thousands of sessions. In this paper, we propose a novel RAM-based searching engine (RSE) to speed up the searching process by using the concept of hierarchical searching with a tree data structure. The time for searching the smallest time stamp is independent of the number of sessions in the system and is only bounded by the memory accesses needed. The RSE can be implemented with commercial memory and field programmable gate array (FPGA) chips in a cost-effective manner. With the extension of the RSE, we propose a two-dimensional (2-D) RSE architecture to implement a general shaper-scheduler. Other challenging issues, such as time-stamp overflow and aging, are also addressed in the paper     

卫星数据分发系统中的分组级FEC技术性能分析

本文根据所给出的信道差错模型和里德所罗门删除码(RSE)编码技术,研究了在卫星数据分发系统中采用分组级前向纠错(FEC)技术的文件成功分发概率和吞吐量效率与文件长度、分组长度、接收站点数及RSE码纠错能力之间的关系,所得到的结论对于卫星数据分发系统中的参数选择及性能优化具有指导意义。     

无线移动终端辐射杂散测试

辐射杂散测试是评估无线移动终端辐射性能的有效方法。文章阐述了进行无线移动终端辐射杂散测试的技术要求、限值和测试方法;着重总结和归纳了在测试过程中需要注意的技术细节;同时对LTE移动终端辐射测试的带来的新问题进行了预分析。     

射频/微波能量收集系统的整流电路研究进展

射频/微波能量收集系统以可持续、环保等优点在无线传感器网络、可穿戴设备等领域具有广泛应用前景。对近年来射频/微波能量收集系统的整流电路的研究进展进行了概述。分析并讨论了整流电路的技术指标和电路结构,分别从器件研究和电路设计两个方面对整流电路的研究进展进行分析、归纳。从原理、性能提升等方面分析具有低的零偏压电阻值的自旋二极管应用于微瓦量级信号整流电路的潜力;从微弱信号整流、宽输入功率范围信号整流、高功率转换效率整流、阻抗去敏感化4个方面分析了整流电路设计的关键问题,归纳出有效的解决途径并对整流电路的发展趋势进行了展望。