5G基站电磁辐射

基于5G基站前向功率控制和波束赋形等关键技术,设计单用户情况下5G基站电磁辐射测试方案。该方案根据电磁辐射功率密度随着距离平方减小的规律布点,可以在一定程度上提高宏基站测试效率。对本文所提监测方案进行现场实测,监测结果远小于国际非电离辐射防护委员会(ICNIRP)标准限值,表明5G基站电磁辐射水平总体可控。利用高频结构仿真器(HFSS)设计5G基站天线模型获取大规模多输入多输出(MIMO)天线阵方向图,基于实际场景电磁参数分析搭建场景,通过射线追踪算法对5G基站的电磁辐射进行预测。预测与监测结果相比误差不大,证明预测方法可靠。     

Fully Programmable Memory BIST for Commodity DRAMs

To accomplish a high‐speed test on low‐speed automatic test equipment (ATE), a new instruction‐based fully programmable memory built‐in self‐test (BIST) is proposed. The proposed memory BIST generates a high‐speed internal clock signal by multiplying an external low‐speed clock signal from an ATE by a clock multiplier embedded in a DRAM. For maximum programmability and small area overhead, the proposed memory BIST stores the unique sets of instructions and corresponding test sequences that are implicit within the test algorithms that it receives from an external ATE. The proposed memory BIST is managed by an external ATE on‐the‐fly to perform complicated and hard‐to‐implement functions, such as loop operations and refresh‐interrupts. Therefore, the proposed memory BIST has a simple hardware structure compared to conventional memory BIST schemes. The proposed memory BIST is a practical test solution for reducing the overall test cost for the mass production of commodity DDRx SDRAMs.     

基于区域约束的机场场面目标跟踪

现有的可靠性鉴定试验方案在一定的风险约束下需要较大的试验工作量,而大型复杂装备受经费、试验条件等因素的限制难以进行大量的试验。针对这一问题,以整机故障率为验证指标,提出利用分系统试验数据制定整机可靠性鉴定试验方案的新方法。该方法首先利用分系统试验数据计算整机故障率置信上限,然后利用两点分位数方法确定整机故障率的先验分布参数,最后依据贝叶斯最大后验风险准则制定了新的可靠性鉴定试验方案。实例对比分析表明,与传统试验方案相比,新方案将明显节约试验时间,减少试验工作量。     

Active sound control in composite regions

In active sound control, noise shielding of a target region is achieved via additional sources (called controls) situated at the perimeter of the region. The sources protect the target region by adjusting the acoustic field near the boundary of the region. In the present paper a numerical model of active sound control based on surface potentials in 3D bounded composite regions is numerically studied. In the composite region setup, it is required that the regions be shielded from noise while allowing admissible sound that is generated in the shielded regions to be preserved. The admissible sound is usually required to propagate freely inside the protected regions or in a (selective) predetermined pattern. The adjusting approach used here does not require any knowledge of the sound sources or the properties of the propagation medium in order to obtain the controls. Moreover, the approach differs sharply from some other approaches where the detailed knowledge of the sound sources and the propagation medium is required. For the first time, numerical test cases involving both free communication and predetermined communication pattern between the regions in three dimensions are considered. In all test cases, these regions are effectively shielded from the noise while any present admissible sound is preserved. In addition, selective propagation of the admissible sound between the regions is enforced. The effect of the number of controls on their operation is also studied. Whether admissible sound is present or not, the level of noise cancellation decreases linearly as fewer controls are used. In addition to the increase in size of the interference zone, the controls become individually distinguishable.     

移动通讯终端产品电磁兼容测试分析

随着人们对周围电磁环境的关注,为了保护人身安全及生态环境,各国要求对电子产品的电磁兼容性（EMC,Electro Magnetic Compatibility）强制认证,通过对中国、欧洲的EMC测试情况分析,介绍了中国和欧洲移动通讯终端产品EMC测试的具体内容,包括所采用的测试标准,所含测试项目和限值要求。目前中国和欧洲的EMC测试要求不一,对中国和欧洲EMC测试中不同点进行了分析总结,为国内与欧洲移动通讯终端产品的认证提供信息。     

LTE网络S1/X2接口一致性测试关键技术研究

文章介绍了LTE网络接口（S1/X2接口）的测试规范以及协议一致性测试的基本模型,并针对一致性测试的关键技术进行了具体的分析和研究,能够为今后S1/X2接口标准化评估提供重要参考,具有一定的工程应用价值。     

手机电磁兼容测试常见问题分析及相关性能改进

针对手机电磁兼容测试中经常出现的问题,包括静电放电抗扰度试验、电快速瞬变脉冲群抗扰度试验、辐射骚扰及传导骚扰性能测试中经常发现的问题进行了分析,并提出了相应的改善手机电磁兼容性能的建议。     

冲击声声品质的基本属性分析

在"愉悦"、"趣味"、"活泼"、"危险"、"震撼"、"紧张"六种情感心理尺度上对冲击声进行主观评价实验,通过因子分析得到"刺激性"、"舒适性"作为冲击声声品质的基本属性.将冲击声声品质基本属性与冲击声信号的客观参数进行关联分析并采用合成冲击声信号进行主观实验,得到"刺激性"与信号衰减时长、起振时长之间的关系,以及"舒适...     

辽宁营口奥体中心综合性体育馆建声设计

近年来,随着中国体育产业的蓬勃发展,综合性体育场馆的建设越来越受到人们的重视,对该类场馆功能的要求也越来越高.建筑声学设计,是体现体育场馆综合功能的一项重要内容.辽宁营口奥体中心是一个典型的大型综合性体育馆,馆内采取了一系列声学设计,为其馆内比赛及演出提供了良好的室内声环境.以营口奥体中心为例,探讨了建筑声学设计在综合...     

运动图像清晰度测试序列设计及发生技术研究

平板显示器的运动图像清晰度比静态会有所恶化,目前国内外有多种主观或客观测试方法,运动图像测试用视频发生器是相关测试所必须的。采用Matlab设计了主观客观通用并可以产生各种运动速度的运动图像清晰度测试序列,并采用非线性编辑平台作为视频播出平台。通过无损压缩和缓存技术,实现了1 920×1 080i/50 Hz序列的实时播放。通过与TG700及VM5000的比对试验发现,视频发生系统的多波群频率响应达到1%,3 dB带宽达到了30 MHz,可以满足1 000线以内静态及动态清晰度的主观评价及客观测试的需求。