基于FPGA的信标光精细跟踪系统设计

介绍了精细跟踪系统的算法及硬件结构组成.以平均值平滑滤波法和质心法实现了对信标光斑定位,利用卡尔曼预测算法实现了具有自适应能力的递归跟踪算法.采用高帧频CMOS相机和高效的基于FPGA处理器的处理算法,实现了信标光的高精度实时跟踪及硬件系统.用外场激光无线通信实验验证了系统具有很好的实用价值.     

星地光通信中的精跟踪模拟实验研究

设计了一套简便易行的星地光通信中精跟踪演示系统方案,并详细介绍了精跟踪演示系统的组成.跟踪算法采用改进神经网络的PID算法,在线调整网络加权值.最后,针对不同频率的信标抖动进行了跟踪补偿模拟实验,实验结果表明,该精跟踪系统实现了高频信标光抖动跟踪补偿,具有很好的实用性.     

空间移动平台信标光的地面模拟捕获与跟踪实验

采用TMS320LF2407A与TMS320DM642的双(DSP)新颖设计,运用卡尔曼预测模型实现了一种新型空间移动平台光通信的信标光扫描、跟踪控制系统.详细论述了系统的硬件、软件设计,给出不同实验条件下的信标光捕获时间,并分析了信标光捕获时间误差和减少捕获时间误差的方法.地面模拟空间移动平台信标光捕获实验表明,信标光捕获与跟踪精度高、扫描速度快,该实验系统具有很好的实用价值.     

湖面自由空间光通信信标光的粗跟踪设计与实验

以湖面信标光为真实移动跟踪目标,设计了二维粗跟踪演示系统,验证空间光通信捕获、跟踪和对准(ATP)系统对机动目标的跟踪性能。采用双DSP和两轴精密转台搭建了粗跟踪的硬件平台。采用直方图阈值分割法将信标光从复杂的湖面背景中分离出来。采用预测自校正控制算法设计粗跟踪系统的控制器,具有较好的鲁棒性。进行了针对湖面移动信标光的二维跟踪实验,实验结果表明,粗跟踪系统有较好的跟踪精度,跟踪精度与跟踪距离远近关系不大,满足空间光通信跟踪系统的要求。     

移动信标光跟踪仿真研究

针对移动信标光跟踪系统的高精度和高稳定性的要求,设计了移动信标光跟踪仿真系统。采用双DSP和两轴精密转台搭建了粗跟踪的硬件平台。采用中值滤波来消除光斑图像的噪声干扰,质心算法实现对光斑位置的精确提取。采用仿人智能PID控制来改善系统动态跟踪性能,增强了系统对不确定因素的适应性。进行了模拟仿真台运动下的二维动态跟踪实验,实验结果表明跟踪系统有较好的跟踪精度。     

基于DM642的信标光实时图像处理

信标光图像处理是完成空间移动平台光通信跟踪和捕获的一种过程.文章具体讲述了在DM642平台上视频设备驱动程序的开发过程,在图像处理中采用最大中值滤波和质心法能有效地提取目标,应用卡尔曼预测算法能有效地跟踪目标运动轨迹.     

空间光通信精跟踪系统地面模拟实验

提出了一套简便易行的空间光通信精跟踪演示系统方案,详细介绍了精跟踪演示系统的组成。信标光斑定位和跟踪算法决定了跟踪带宽,信标光斑定位的传统方法存在系统误差和随机误差,采用像元细分对误差进行校正;跟踪算法采用改进神经网络算法,利用神经网络的自学习和自适应能力,在线调整网络加权值,增强了系统的实时跟踪性能。最后分析了像元细分对定位精度的改善,比较了不同定位算法的跟踪性能,改进的神经网络算法提高了精跟踪系统的鲁棒性。采用400Hz的CCD,针对不同频率的信标抖动进行跟踪补偿实验,实验结果表明,50Hz的信标光抖动范围压缩了25.7%。     

基于GPS的星地激光通信捕获对准研究

提出了基于GPS坐标解算实现星地激光通信捕获、跟踪和对准(ATP)初始捕获的方法。星地激光通信信标光跟踪系统通过对地面GPS坐标和卫星坐标的解算,得到地面光学天线的方位角和俯仰角,光学天线根据角度旋转对准信标光,从而将信标光引入粗跟踪CCD的视场。给出了GPS坐标解算算法和信标光方向角度随卫星坐标变化的仿真曲线。用二维电机进行了地面转台的捕获实验,对实验数据进行了捕获精度的分析,结果表明,通过GPS坐标解算能够快速地实现信标光的初始捕获。     

基于ARM的空间光通信APT控制系统设计

设计一种基于ARM嵌入式处理器为核心的控制系统,该系统主要完成在空间无线光通信中信标光的扫描、捕获和跟踪控制,即APT控制系统.以光栅螺旋扫描算法实现信标光的扫描、捕获功能,用增量式PID控制算法实现信标光的跟踪控制功能.该设计具有高实时性、高集成度、低功耗等优点,可满足空间光通信中APT控制部分的要求.     

基于协议的信标快速提取有源实现

针对在强背景或假目标持续干扰的情况下,常规图像处理算法较难实现对信标进行准确快速提取的问题,提出了一种基于握手协议的APT信标快速识别系统,给出了系统的设计原理.提出一种基于图像边缘闭曲线拟合的虚警判据,能对潜在假目标进行准确的识剐判断.实验数据表明:在复杂背景和人工虚警干预情况下,系统能对信标光进行准确定位,具有一定的稳健性.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.