厦门市700 MHz频谱使用现状及干扰隐患

5G系统是我国实施“两个强国”战略的重要信息基础设施,更是发展新一代信息通信技术的高地。700 MHz作为最新规划的5G低频段频谱资源,将进一步提升5G通信技术的发展。重点介绍了厦门市700 MHz频谱的使用现状,存在的干扰隐患及解决建议。     

小区间动态干扰协调的改进方案

对下一代移动通信系统的小区间动态干扰协调算法进行研究,通过分析干扰水平,负载状况,基站的调节能力以及用户的位置,通过负载因子变化来接纳控制,提高边缘用户的数据传输速度,保证小区用户的公平性。通过上行功率控制及接纳算法改进方案;同时对小区用户划分区域设定,提出了小区间干扰协调的改进算法(ICPF), 并进行系统仿真计算分析,结果表明和以往传统算法相比,系统性能得到有效改进,进一步提高了系统公平性并增加小区边缘用户的吞吐量。     

基于多模干涉和长周期光纤光栅的温度及折射率同时测量

基于多模干涉理论和长周期光纤光栅(LPFG)的传感特性,提出了一种单模-多模-单模(SMS)结构与LPFG级联的光纤传感器,实现了温度和折射率的同时测量。实验结果表明,SMS结构的干涉谱和LPFG对温度和折射率具有不同响应灵敏度,其温度灵敏度分别为0.017nm/℃和0.060nm/℃;SMS结构对折射率不敏感,而LPFG的折射率灵敏度为-35.60nm/RIU(RIU为折射率单位)。因此利用敏感矩阵,实现对温度和折射率的同时测量,得到温度和折射率的最大测量误差分别为±0.59℃和±0.0013。该结构灵敏度高、结构简单,且不易受电磁等干扰。实验结果具有良好的线性度,在生物化学领域应用前景良好。     

激光干扰下红外成像系统性能预测研究

激光干扰是抑制红外成像系统现场性能的有效手段,为实现对激光干扰下红外成像系统性能预测,文中以激光干扰红外成像探测器的作用机理为基础,通过对红外成像系统吸收的激光能量与对比度增强之间的关系进行分析,得到干扰激光的能量与对比度增强之间的关系,进而修正红外成像系统的对比度阈值函数;并结合NVThermIP性能模型实现激光干扰对系统性能的预测,给出了仿真结果,为红外成像系统的性能预测评估和理论模型的继续完善提供依据。     

Ta2O5/SiO2硬膜双腔滤光片激光损伤特性研究

研究了Ta2O5／SiO2硬膜双腔干涉滤光片带内、带边及带外的吸收和激光损伤特性。实验发现，对于作用激光，带通滤光片的驻波场分布、吸收率和损伤阈值在带内、带边和带外的响应特性对作用激光波长均呈现出明显的选择性。根据实验结果，结合滤光片的驻波场分析，给出了带通滤光片的损伤机理。     

实时全息干涉计量术的发展近况和趋势

本文综述了实时全息干涉计量术的发展近况。介绍了实时全息干涉计量术的某些新方法,新装置及其所依据的原理并论述其发展趋势。     

液晶光学相控阵相位调制特性测量

为了测试设计波长为1550 nm的液晶光学相控阵在633 nm波段的相位调制特性,采用泰曼格林干涉法和偏振光干涉法相结合的方法来进行测量。实验结果表明,液晶光学相控阵的相位延迟随灰度近似呈线性分布,在0~255的灰度范围内针对633 nm激光的实际相位调制在0~3.76π之间,在135~255的灰度范围内线性度良好,可以作为液晶的工作区域。由于液晶相位控制的准确性和精度是通过加载相应的灰度来实现的,因此测量相位延迟和灰度对应关系的研究对于液晶光学相控阵用于高精度光束偏转和跟踪有着重要价值。     

Cascode Monolithic DC-DC Converter for Reliable Operation at High Input Voltages

A CMOS OTA-C low-pass notch filter for EEG application is described. The pass-band covers four bands of brain wave and provides more than 65 dB attenuation for the 50 Hz power line interference. The OTA works in the weak inversion region and a low transconductance of 3 nA/V is achieved. The low transconductance enables using small capacitors in the OTA-C filter so that the filter is suitable for the multi-channel EEG integrated circuits. The measured results show the good performance of the filter for filtering the noise in acquired EEG signals. Xinbo Qian received the B.Sc. degree from Beijing Institute of Technology, P.R. China, in 1991 and M.Sc. degree from Institute of Physics, Chinese Academy of Sciences, in 1996. From 1996 to 1999, she was a research engineer in the Institute of Acoustics, Chinese Academy of Sciences, worked on the sonar signal receiving and processing systems. Since 1999, she has been pursuing the Ph.D. degree in Electrical and Computer Engineering department, National University of Singapore, with research direction on on-chip readout circuits for microbolometer focal plane arrays. Now she is employed by Department of Mechanical Engineering and Division of Bioengineering, National University of Singapore as a research fellow. Her research interest is low-noise integrated circuits design and bio-medical sensor electronics, including electroencephalography IC, magnetocardiography IC, low-noise amplifier, filter and data converters etc. Yong Ping Xu graduated from Nanjing University, P.R. China in 1977. He received his Ph.D. from University of New South Wales (UNSW) Australia, in 1994. From 1978 to 1987, he was with Qingdao Semiconductor Research Institute, P.R. China, initially as an IC design engineer, and later the deputy R&D manager and the Director. From 1989 to 1992, he was working on silicon diode based infrared detectors towards his Ph.D. at School of Electrical Engineering, UNSW Australia. From 1993 to 1995, he worked on an industry collaboration project with GEC Marconi, Sydney, Australia, at the same university, involved in design of sigma-delta ADCs. He was a lecturer at University of South Australia, Adelaide, Australia from 1996 to 1998. He has been with the Department of Electrical and Computer Engineering, National University of Singapore since June 1998 and is now an Associate Professor. His general research interests are in the areas of mixed-signal and RF integrated circuits, and integrated MEMS and sensing systems. His current focuses are high-speed wideband ADC, UWB front-end circuits and low-power low-voltage integrated circuits for biomedical applications. He is a Senior Member of IEEE. Xiaoping Li received his Ph.D. degree from Department of Mechanical and Manufacturing Engineering, University of New South Wales, Australia in 1991, and joined the National University of Singapore in 1992, where he is currently an Associate Professor with the Department of Mechanical Engineering and Division of Bioengineering. He was a visiting professor of Tokyo Institute of Technology, Japan in 2000, and visiting professor of Georgia Institute of Technology, USA in 2001. He is a member of American Society of Mechanical Engineers (ASME), a senior member of Society of Manufacturing Engineering (SME) and a senior member of North American Manufacturing Research Institute/SME, and is currently the Chairman of SME Singapore Chapter. His current research interests include neurosensors and nanomachining. He is a guest editor of International Journal of Computer Applications in Technology, USA. He is a regular reviewer of the ASME Journal of Manufacturing Engineering, USA, Transactions of NAMRI/SME, USA, Journal of materials processing technology, UK, International Journal of Machine Tools and Manufacture, UK, and IMechE Journal of Engineering Manufacture, UK.     

逆合成孔径雷达(ISAR)干扰仿真研究

目前逆合成孔径雷达(ISAR)在军事上的作用越来越突出,是目标分类、辨识和战场上敌我识别以及精确制导强有力的手段,在未来防空和导弹防御系统中具有十分重要的作用。本文分析了ISAR成像原理,建立了ISAR系统的仿真模型,并在此基础上对几种干扰技术进行了仿真。     

LED显示屏驱动电流的潜在电磁干扰分析

为了控制对发光二极管(LED)显示屏亮度调制时电 源电流产生的电磁干扰(EMI),对3种脉冲宽度调制(PWM)调光方法下显示 屏的电源电流频谱进行了研究。首先比较了线性、离散和选通3种PWM的调光原理和潜在 EMI,设计了基于电流频谱分析的EMI评估法,并通过对单亮度和亮度均匀渐变图像 的仿真,验证了评 估法的有效性;最后通过对LED显示屏真实图像显示时的电流频谱分析,比较了3种调光方 法的潜在EMI。实验结果表明:线性PWM方式下,同时点亮LED会产生较大的EMI;离 散PWM对消耗电流的 延展和码制对消作用,可以有效地减小EMI;选通PWM随着选通等级的提高,最小点 亮脉冲变窄不利 于减小EMI。本文的分析结果可用于在LED显示屏产品设计时,合理进行EMI分析 与分配,预估产品的电磁兼容性。