光纤磁场传感器信号解调方法及仿真研究

为了减少相位随机漂移和1/f噪声对信号检测灵敏度的影响,基于磁致伸缩效应的光纤干涉型磁场传感器必需在传感臂或参考臂施加高频调制磁场;考虑负载效应、退磁效应,给出了光纤/磁致伸缩耦合结构的等效应变;采用相位载波(PGC)外调制方案,在参考臂施加高频调制磁场,根据贝塞尔函数展开式,建立了被测磁场与载波磁场振幅、调制磁场振幅之间的关系式;借助Matlab/Simu-link,对相位解调方法进行仿真,仿真结果与理论分析结果十分吻合;研究了输出信号幅值随调制磁场幅值变化的趋势,得到高频调制磁场幅值的最优值。     

正弦波调制对谐振式陀螺中谐振信号的影响

谐振式光纤陀螺（R—FOG）是利用光学Sagnac效应实现对转动角速度检测的一种高精度惯性传感器件。理论分析了正弦波调制特性,搭建了光学微谐振腔的调制解调实验系统,实验对比了正弦波、锯齿波、三角波3种调制波形对谐振信号信噪比的影响,得出了正弦波调制效果最好,提高了谐振信号的信噪比。针对不同调制幅度和频率条件下的正弦波调制对谐振信号的影响进行了测试,得出了调制幅度和调制频率对谐振信号的影响,为光学微谐振腔在谐振式陀螺系统应用中相位调制选择最佳的参数提供了参考。     

基于Matlab干涉型光纤水听器调制与解调仿真

该文概述了Mach—Zehnder干涉型光纤水听器两种相位载波调制（PGC）原理,着重分析直接调制半导体激光器的相位载波的信号解调,及在解调技术中伴生调幅的影响及解决办法,并根据直接调制光源的PGC零差检测方案电路系统,仿真搭建了Matlab的Simulink系统,通过改变载波频率、被测信号频率与被测信号幅度,用大量的Matlab仿真图形分析指出,直接调制光源实现相位载波技术中,载波频率、被测信号频率与被测信号幅度对系统解调输出结果的影响,实践证明该结果对水听器组阵具有很好的理论指导作用。     

相位调制型光纤压力传感器与智能检测系统

介绍了光纤传感器检测系统的特点和结构组成。重点分析了相位调制型光纤压力检测系统的原理及以单片机为核心的信号处理方法 ,最后给出实验结果     

数字闭环光纤电流互感器死区形成机理分析

死区是闭环反馈控制系统中常见非线性现象之一,其产生原因是由于增量型非比例反馈通道干扰的存在.在干涉型数字闭环光纤电流互感器系统中,死区将引致系统零偏、零漂等非线性现象.通过系统模型的建立与分析发现,除正常相位补偿机制需要的比例反馈通道外,相位调制信号与光电探测器输出间的交叉电信号耦合、相位调制信号控制误差与相位调制器性能漂移,将在闭环光纤电流互感器中形成了另外一条非比例的干扰反馈通道;干扰通道与干扰信号的相关参数,不仅决定着死区的产生条件,也为抑制死区现象提供有效的解决途径;实验表明,死区现象的非比例反馈通道解释,不仅具有理论上的合理性,而且得到实验结果的支持.     

基于压电陶瓷相位调制器的外调制相位生成载波法研究

对基于压电换能器PZT(Piezoelectric Transducer)的外调制相位生成载波PGC(Phase-Generated Carrier)法进行了深入的理论分析和实验研究.PZT光纤相位调制器利用电致伸缩效应来改变缠绕在其上面的光纤的长度,进而实现对光纤中光相位的周期性调制.在马赫曾德尔光纤干涉仪MZI(Mach-Zehnder Interferometer)的参考臂中加入该光纤相位调制器便可以将载波信号调制到光纤干涉仪的输出信号当中.计算机仿真分析了调制参数对PGC解调结果的影响.并通过实验验证了这种调制解调方案的可行性.利用美国国家仪器公司的数据采集系统及Labview编写的解调算法,在臂长为200 m的MZI中成功实现了相位解调,恢复出MZI传感臂中的原始相位信息,解调信号与原始信号的相关系数在0.99以上.     

光纤振动传感系统相位调制模块的嵌入式设计

针对光纤振动传感系统测试与标定环节缺乏便携式振动信号驱动装置的问题,设计了一款基于FreeRTOS和STemWin嵌入式系统的压电陶瓷相位调制模块.该模块使用STM32嵌入式微控制器,结合H桥功率驱动对信号进行功率放大.利用FreeRTOS嵌入式操作系统进行多任务功能部件开发,并设计了STemWin人机交互界面.随后搭建分布式光纤振动传感系统对嵌入式相位调制模块进行测试,结果表明该模块可实现驱动信号频率、占空比、输出极性和电压的调节,并可在总长为11.769km的传感光纤上对冲击信号进行实时采集,且振动信号定位误差在41m以内,从而可满足各类光纤振动传感系统在长距离不同位置处进行振动测试与标定的需求.     

基于M-Z动态干涉仪的全光纤麦克风研究

设计了一种新型的全光纤干涉型型麦克风.通过构造由光纤耦合器和镀铝振膜组成的动态M-Z干涉光路,将外界声压对振膜的作用转化为对光路相位的调制,得到的输出光信号光电转换后可直接提取出原声音信号.整个光路和光纤探头部分无任何电的参与,具有抗电磁干扰、尺寸小、灵敏度高等优点.并通过实验对该光纤麦克风进行了测试,得到了较好的实验结果.     

Mach-Zehnder光纤干涉仪相位检测方案研究

本文根据Ｍａｃｈ－Ｚｅｈｎｄｅｒ光纤干涉仪相位调制及双光束干涉测量的特点,介绍了一种采用相位调制器（ＰＺＴ）实现相位载波调制,利用Ｂｅｓｓｅｌ函数进行傅里叶分解实现对相位调制信号解调的检测方案。理论分析表明,该方案能有效地抑止随机干扰信号对测量精度的影响。     

干涉型光纤水听器相位载波解调技术

通过数学推导和仿真分析,对直接调制光源产生相位载波的马赫-曾德尔(Mach Zehnder)干涉型光纤水听器调制解调技术进行了研究。提出了不能通过干涉信号的峰值或峰峰值检测来控制自动增益控制(AGC)电路增益的方法消除偏振衰落对输出信号的影响。在这一思想的指导下完成了光纤水听器相位载波(PGC)解调电路的设计,给出了实验测试结果。     

基于多角度光学投影表面重建的三维自发荧光光源定位算法

在自发荧光断层成像（Bioluminescent tomography imaging,BLT）中,双模态融合（光学模态与结构模态）可充分利用结构模态提供的高精度3D几何结构,重建三维表面荧光光通量分布,进而实现小动物内部荧光光源定位.然而,与纯光学模态相比,双模态融合存在采集系统复杂、成本高、数据处理繁琐及存在电离辐射（如CT）等问题.因此,研究基于纯光学3D几何结构的自发荧光光源定位方法对BLT具有重要意义. 本文在搭建纯光学自发荧光断层系统（All-optical bioluminescence tomography system,AOBTS）的基础上,提出一种基于多角度光学投影表面重建的三维自发荧光光源定位方法. 本方法由基于多角度光学投影的3D表面重建、多角度荧光无缝融合、荧光光通量的量化校正以及自发荧光内部光源重建4部分组成. 通过真实小鼠内部植入荧光光源实验表明,与传统纯光学方法相比,本文提出方法不仅改进了3D表面重建方法,而且增加了多角度荧光无缝融合,可实现真实小鼠的三维自发荧光光源定位,初步实验证明具有小动物预临床实验潜力.     

All-optical binary flip-flop with the help of Terahertz Optical Asymmetric Demultiplexer

The memory device is very important as they store various values either temporary or permanently. Optical flip-flop memories form a fundamental building block for all-optical packet switches in the next generation communication networks. All-optical flip-flop memory with the help of Terahertz Optical Asymmetric Demultiplexer (TOAD) is proposed and described. Principles and possibilities of all-optical circuits for TOAD based S–R, J–K, D and T flip-flop are reported. Numerical simulation confirming described method is also given in this paper.     

全光网络中波长转换器配置问题的蚁群算法

研究提高网络的利用率,在全光网络中放置波长转换器是打破波长一致性约束,为了降低网络阻塞率,提高网络通信能力的有效途径。但限于波长转换器的高昂成本,不可能为网络中的每个节点都配置波长转换器,所以波长转换器应以最优方案放置在网络中的个别关键节点上。提出了一种基于蚁群算法的波长转换器配置方法,通过蚁群算法寻找给定网络中任意源、目的节点之间的最优路径,并利用蚂蚁对最优路径的记录,统计路径在节点处发生波长转换的次数,将具有较高波长转换次数的节点作为网络中波长转换器放置节点。最后通过对一个5节点的网络进行算法演示和仿真分析,结果表明该算法能求得波长转换器的合理配置,得到较好的通信效果。     

WDM全光网络中Multicast的寻径与波长分配算法

在WDM全光网络中实现实时Multicast功能是计算机网络的应用要求,也是现代计算机网络的重要特征。该文提出了一种在WDM全光网络中实现实时Multicast的算法。该算法以辅助的波长图为基础,将寻径与波长分配统一进行,构造满足延迟约束的、具有较低成本的Multicast树,实现Multicast功能。     

基于LQR的直升机最优控制系统的设计

设计了直升机LQR最优控制系统，并针对LQR控制中加权矩阵和难以确定的问题，进行了试验分析，从实际控制效果出发．找出了系统响应与和之间遵循的规律，为在利用该方法进行其它控制系统设计中和的选取提供了参考。     

全光网络浅析

摘要：阐述了全光网络是未来信息发展的一个必然趋势,分别介绍了全光网络的组成、结构、优越性、100Gb／s所面临的问题、安全隐患及探讨中的保护措施,进而从一定层面上呈现给读者一个全光网络的总体特征。     

全光网波长转换器配置问题的一种启发式算法

波长转换技术可以消除全光网络中的波长一致性限制,降低网络阻塞率,因此在具有波长转换器的全光网中,如何通过合理配置、使用数量有限的波长转换器来最大程度的降低网络的阻塞率,这是全光网络需要解决的一个关键问题。因此对网络中通过节点的路由数量、通信量、路由长度及节点处于路由的中心距离进行分析,并给上述四个参数赋予一定的权重进行加权处理,提出了一种基于节点权的全光网络波长转换器配置算法,并针对一般拓扑网络进行了算法演示和分析。     

Optical packet switching with multiple path routing

The performance of packet-switching wavelength routed optical networks critically depends on packet contentions at the intermediate routers. This paper shows through simulations that deflection routing is an effective technique for packet-switching wavelength routed optical networks with irregular meshed topologies. It is shown that multiple path routing (MPR) as the deflection rule mitigates the blocking of packets substantially in cross-connected all-optical networks leading to a significant reduction in hardware volume and cost of all-optical IP routers. The effectiveness of the blocking reduction critically depends on the network topology, and meshed topologies with a high number of interconnections benefit of the largest gain from deflection routing.     

Sag feedback based multi-roll coordinating optimal control of a low-tension roll-to-roll system

The roll-to-roll (R2R) system is crucial for manufacturing low-strength sheets. And the speed control of rolls in this multi-roll system has a significant influence on the quality of the fragile sheets. However, the previous system with tension-based feedback control methods might crack the low-tension sheets during transportation. And few studies have carried out other effective control strategies for the R2R system. In this paper, the sag of sheets between rolls is chosen to be the feedback quantity, which provides a low-tension condition. A multi-roll coordinating optimal control method for the R2R system is introduced to keep sags stable by adjusting rolls’ speeds when the linear velocity of the upstream roll changes. A multiple-input multiple-output (MIMO) linear-quadratic-integral (LQI) controller is designed for the system. Several simulations and experiments are performed to confirm its validity. The effects of the hyperparameters in the proposed controller are also investigated. Compared with the series single-input single-output (SISO) PID control method, the proposed control method does better in reducing the speed fluctuation and eliminating error propagation and amplification in the low-tension R2R system. This control method and controller meet the needs of manufacturing low-strength sheets and show potential in enhancing the performance of the R2R system.     

Human factors evaluations of Free Flight Issues solved and issues remaining

The Dutch National Aerospace Laboratory (NLR) has conducted extensive human-in-the-loop simulation experiments in NLR's Research Flight Simulator (RFS), focussed on human factors evaluation of Free Flight. Eight years of research, in co-operation with partners in the United States and Europe, has shown that Free Flight has the potential to increase airspace capacity by at least a factor of 3. Expected traffic loads and conflict rates for the year 2020 appear to be no major problem for professional airline crews participating in flight simulation experiments. Flight efficiency is significantly improved by user-preferred routings, including cruise climbs, while pilot workload is only slightly increased compared to today's reference. Detailed results from three projects and six human-in-the-loop experiments in NLR's Research Flight Simulator are reported. The main focus of these results is on human factors issues and particularly workload, measured both subjectively and objectively. An extensive discussion is included on many human factors issues resolved during the experiments, but also open issues are identified. An intent-based Conflict Detection and Resolution (CD&R) system provides "benefits" in terms of reduced pilot workload, but also "costs" in terms of complexity, need for priority rules, potential compatibility problems between different brands of Flight Management Systems and large bandwidth. Moreover, the intent-based system is not effective at solving multi-aircraft conflicts. A state-based CD&R system also provides "benefits" and "costs". Benefits compared to the full intent-based system are simplicity, low bandwidth requirements, easy to retrofit (no requirements to change avionics infrastructure) and the ability to solve multi-aircraft conflicts in parallel. The "costs" involve a somewhat higher pilot workload in similar circumstances, the smaller look-ahead time which results in less efficient resolution manoeuvres and the sometimes false/nuisance alerts due to missing intent information. The optimal CD&R system (in terms of costs versus benefits) has been suggested to be state-based CD&R with the addition of intended or target flight level. This combination of state-based CD&R with a limited amount of intent provides "the best of both worlds". Studying this CD&R system is still an open issue.