广播电视信号调频副载波光纤传输技术研究

当前,光纤传输使用复用调制的方式缓解频率选择性衰落,但多载波调制会造成信号传输功率的降低,从而导致频带互调失真。为此,对广播电视信号调频副载波光纤传输技术进行研究。在接收端对频率和相位偏移进行补偿,将插入导频的载波相位移动90°,恢复调频副载波。预先设定峰值平均功率比(PAPR)阈值,单独处理每个频带信号,对光纤基带信号进行峰值消减,利用快速傅里叶变换(FFT)将光纤基带信号从时域转换至频域,保留全部带内信号,过滤带外频谱,实现光电转换。测试结果表明,提出的光纤传输技术能够实现较好的非线性补偿,具有较低的误差矢量幅度(EVM)和较高的邻信道功率比(ACPR),提高了光纤传输性能。     

自检式冲击波参量检测系统设计

针对冲击波参量检测与系统可靠性问题,设计了一种带自检功能的冲击波参量检测系统。传感头采用自发光式光纤镀膜探针,光纤探针在冲击高压下发光,并通过高速光电转换与示波器记录冲击响应信号,实现对冲击波参量检测。将激光脉冲耦合入传感光路,通过检测激光脉冲在镀膜光纤探针端面镀膜层的反射脉冲信号实现系统自检。详细介绍了镀膜光纤探针、高速光电转换电路及半导体激光器脉冲驱动源的设计与实现。进行了TNT爆轰驱动条件下冲击波到达时间的测量,实验结果表明：整系统的冲击波响应信号前沿小于5ns,测量不确定度小于3ns,为爆轰物理和冲击波物理实验中冲击波参量检测提供了一种可靠有效的测试手段。     

像素级模拟视频光纤传输系统的设计

光电跟踪设备的模拟视频光纤传输一般是经过A/D转换以后,把数字量经过物理层的协议转换,再进行电光转换。由于电磁环境复杂,传输过程中容易耦合进噪声,导致接收端恢复的图像出现噪声点和干扰条纹。提出了利用视频解码器,分离出视频流的行、场同步信号,在行同步信号的控制下,以行像素数据为单位进行异步光纤系统的设计,再经过视频编码恢复出原始图像。结果表明模拟视频经过该光纤传输系统以后,恢复后的视频图像清晰、没有噪声点和纹波现象,满足了实际工程对高质量模拟视频传输需求。     

用于监测阀门泄漏的超高动态范围全光纤超声传感系统

本文提出了一种超高动态范围的全光纤超声传感系统,针对阀门发生泄漏时伴随产生的声发射现象,利用光纤的光弹效应,将声发射现象产生的超声信号转换为光纤中传输的光信号的相位变化,由光路干涉结构将光信号的相位改变量转换为两路干涉输出信号的幅度量,通过相位解调还原算法和功率谱分析,实现对超声信号的探测和提取。经过阀门泄漏实地测试验证了全光纤超声传感系统的实用性和可行性,并在实验室条件下对系统的动态范围进行了具体的测试分析。     

基于FPGA的多路数据光纤传输系统设计与实现

针对某型作战指挥系统中通信网络的传输信号多样性和复杂性,以及信道利用率低的现状,提出了以1310nm/1550nm光纤作为传输媒介,基十FPGA的多路、多速率模拟/数字信息综合传输的设计方案;采用了多种复用技术将不同种类的信号进行处理,复用到单根光纤上传输,以QuartusII 4.0为编译环境,以VHDL语言为开发工具实现了CMI和HDB3编译码;实验结果表明:系统语音信号清晰,数字信号传输误码率低.工作性能稳定;这说明基于FPGA的多路数据光纤传输系统设计是成功的.     

基于光纤传输的结构损伤声发射监测系统研究

摘要：声发射检测技术作为一种先进的故障诊断技术,在大型起重设备检测行业“大行其道”。由于生产现场的环境比较复杂,不可避免地要受到各种噪声的影响。当前对声发射信号大多是靠电缆进行传输,这种传输方式有传输距离有限、信号容易受到干扰等缺点。针对传统电缆传输信号的不足之处提出使用光纤作为传输信号的媒介,设计并开发了一种基于光纤的声发射监测的信号采集系统,能够实现远程监测且信号的抗干扰能力比较好。     

基于LabVIEW的光纤光栅传感的动态解调

设计了一种基于LabVIEW和可调谐光滤波器的光纤光栅传感动态解调系统。用LabVIEW编写虚拟仪器(VI)程序,通过硬件接口由计算机控制可调谐光滤波器,使其在固定波长范围内扫描;采集电路对光电转换后的信号进行采集并送到计算机中分析处理,得到传感信号的反射波长以获得应变量。最后把传感解调系统的测试结果和光谱仪的测试结果进行比较,两者基本一致,说明了解调系统的设计是正确的。     

全光纤干涉振动信号测试系统的硬件解调系统的研究

本文介绍了一种应用于全光纤干涉振动传感系统的硬件信号相位解调系统。文中对全光纤干涉振动传感系统的信号解调原理进行了介绍和分析,对光电转换和放大过程中所造成的信号被消除直流分量进行了自动计算和补偿;设计并实现了解调光纤传感信号的硬件系统,经过测试硬件信号相位还原系统可以准确有效地还原出设计带宽内的信号,有效地消除了软件还原方法中由于引入量化噪声等导致对信号还原精度的影响。     

一种基于ARM的仿生偏振光测试系统的研究

针对研制仿生导航微纳传感器的需要,设计了一种以光电二极管为光电转换元件、以ARM微处理器为控制核心的仿生偏振光测试系统.分析了仿生偏振光测试的原理,并对测试系统的硬件设计及基于实时操作系统uC/OS-Ⅱ的软件开发进行了详细的阐述.该测试系统成功实现了对特定波段(370 nm-520 nm)的偏振光信号的采集,并利用三路信号进行了定位角度的计算.     

基于V/F转换的高精度模拟信号光纤传输系统

根据电压/频率转换和频率/电压转换的原理,采用LED—PIN光传输结构和相应的模拟集成电路,设计了一个低成本,传输精度可达0.1%的模拟信号光纤传输系统。该系统克服了实际传输模拟小信号的非线性,以及模拟信号A/D转换后采用数字光纤传输技术的成本较高等缺点,为多通道、远距离、低频模拟小信号提供了一个性能优越的传输方案。     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

基于QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

基于AD9626的模拟信号采集存储卡设计

自然界的绝大部分信号都是以模拟的形式存在,因此模拟信号的采集转换存储在数字时代十分关键。文章讨论了在雷达信号处理领域基于AD9626的AD采集存储卡的设计原理、硬件结构和程序设计与芯片配置等问题,为今后相关领域的研究提供了可参考的方案。     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

A human-computer interface for non-computer specialists

The COM teleconferencing system was designed to be easy to use for both beginners and people with much computer experience. A number of design choices in organizing the human-computer interface were considered very carefully. These design problems are not unique for teleconferencing applications, but will appear in many other developments of human-computer interfaces for non-computer specialists. This report discusses naming conventions, menu format, user commands, help facility and the treatment of ‘type ahead’ from the users.