基于高端FPGA的IC验证平台的电源完整性(PI)分析

通用的FPGA(Field Programmable Gate Array,现场可编程逻辑门阵列)验证平台在运行不同的应用时,其瞬态电流需求是不同的。本文以基于Xilinx公司的Virtex-4系列千万门级的FPGA高端IC验证平台为例,采用Cadence PCB PI(Power Integrity)分析软件,对多种地电平面、电容值、电容的放置位置、电容的类型等进行评估,然后通过修正电容数量和额定值,调整电容的布局以及封装等,达到符合要求的电源-地平面目标阻抗,从而将电源/地平面上的噪声降低到电源的要求范围内。本文提出的电源完整性分析方法,对其他类型的系统板级设计也有一定的指导意义。     

移动通信中基于交互差错的协作发射性能研究

未来移动通信系统中相互独立的多个手机通过协作发射可以获得协作分集的好处。同时,发射端信息交互差错会影响协作发射性能。考虑瑞利衰落信道及基于空时分组码的协作发射方案,该文研究了信息交互差错对分集性能的影响。理论分析及仿真结果表明,当信噪比较高时发射端信息交互差错成为影响接收性能的主要因素,发射端协作手机数大于2时,接收端增加接收天线数可在一定程度上提高接收性能极限。     

Optimum Design for RF-to-Optical Up-Converter in Coherent Optical OFDM Systems

In this letter, we conduct analysis on the optimum design for RF-to-optical up-converter in coherent optical OFDM systems using an optical I/Q modulator. We first derive closed-form expressions for the nonlinearity in the optical I/Q modulator, represented by two-tone intermodulation products as a function of the bias point and modulation index. Additionally, we perform a numerical simulation to identify Q-penalty and the excess modulation insertion loss under various transmitter conditions. We find that in contrast to the direct-detected system, the optimal modulator bias point for the coherent system is pi, where the Q-penalty and excess loss are minimized     

Experiment demonstration of micro-Doppler detection of rotor blades with passive coherent location based on digital video broadcast

We propose a realtime passive coherent location (PCL) system based on digital video broadcast (DVB) for the detection of the micro-Doppler (m-D) signature induced by the blades of a helicopter. In this paper, the detailed demonstration of the hardware system, signal processing and field experiment is presented. The m-D parameters of the model helicopter in the experiment are accurately estimated by means of cross ambiguity function (CAF). This paper contributes additional experimental m-D data and analysis, and the effectiveness of micro-motion detection by PCL system is well proved. The attractive merits of DVB based PCL make it more feasible to be widely deployed in urban environment for homeland security purpose. The present work is the first reported realtime system of DVB based PCL for the m-D detecting purpose.     

立体显示技术的中国专利申请状况分析

随着数字电视技术和平板显示技术的发展,立体显示技术逐渐成为当前的研究热点.通过对立体显示技术领域的中国专利申请进行检索和分析,给出该领域的中国专利申请类型、年度申请量、申请区域和重要申请人,并对该领域的中外重要申请人的专利申请情况进行了比较.通过分析,希望能够给中国企业部署未来专利策略提供参考.     

单载波MIMO对流层散射系统的信道估计

针对对流层散射信道的频率选择性,提出了一种基于训练序列的单载波空时分组编码(Space Time Block Code,STBC)系统的信道估计算法。首先建立了单载波空时分组编码系统的系统模型,确定了发送分组结构和接收技术;接着提出了信道估计算法,并讨论该算法中Chu序列的最优性;最后通过仿真分析了信道估计算法的性能和效率。     

风光互补移动电源

针对户外旅行爱好者可能发生的用电短缺的情况,设计了一套便携式风光互补移动电源的系统。该系统充分利用户外易于获得的风能和光能,通过风力发电机和太阳能电池板将风能和太阳能转化为电能的形式存储在锂电池中,并且电路具有过充、温度保护功能。     

高速通信系统 PCB 的电磁兼容性设计

文中从通信系统的信号完整性设计和电磁兼容性设计的概念讲起,重点描述了某高速通信系统的EMC设计方法。该系统基于CPU、FPGA和DDR的核心架构,有信号频率高、交换容量大、板卡EMI指标严格的设计难点。文中在系统的EMC设计过程中重点考虑了高速信号完整性和电源完整性,有效的突破了该高速PCB设计的关键技术,并搭建了测试平台对板卡的信号完整性、电磁辐射进行了全面测试。经实验证明,文中设计的系统信号完整性与电磁兼容性性能优良,充分满足了设计要求,工作稳定可靠。     

模拟电子技术课程项目化教学改革探讨

在传统的模拟电子技术教学中,存在电子元件非线性、电子电路比较复杂、理论知识抽象繁琐、学生学习兴趣低且动手能力差等特点。在这种教学条件下,构建模拟电子技术的项目理实一体化教学,将理论知识寓于实际项目中,实现让学生在动手做实际电子产品中学会模拟电子技术的基础知识,提升动手能力,有利于真正实现高职院校应用型技能型人才的培养目标。     

A MULTILAYER FEEDFORWARD NEURAL NETWORK MODEL FOR VISUAL MOTION PERCEPTION

The local visual motion detection mechanism used in the visual systems of primatescan only sense the motion component oriented perpendicularly to the contrast gradient of thebrightness pattern.But the visual system of higher animals can adaptively determine the actualdirection of motion through a learning process.In this paper a multilayered feedforward neuralnetwork model for perception of visual motion is presented.This model employs W.Reichardt'selementary motion detectors array and T.Kohonen's self-organizing feature map.We explored theself-organizing principles for perception of visual motion.The computer simulations show thatthis neural network is able to recognize the true direction of motion through an unsupervisedlearning process.In addition,the neurons with the same or similar motion direction selectivitytend to appear in“functional columns”which seem to be qualitatively similar to the corticalmotion columns observed by electrophysiological and cytohistochemical studies in certain higherareas such as MT.It proves that motion-detection by spatio-temporal coherences,mapping,co-operation,competition,and Hebb rule may be the basic principles for the self-organization ofvisual motion perception networks.