基于SOPC高精度超声波测距系统研究与实现

为了解决超声波测距精度不高的问题,文章介绍了一种基于SOPC高精度超声波测距系统,采用互相关法测距算 法,以SOPC系统作为信号处理和控制的核心,使用Quartus II和SOPC Builder完成对SOPC系统的定制,系统还设计了温度补偿电路和自动增益电路。测试结果表明,此系统测距相对误差可以达到0.1%,同时抗干扰效果强,具有在线升级功能,有一定的实用性。     

基于Linux和SOPC系统的NFS开发平台设计

主要介绍在Virtex II Pro开发板上搭建一个基于PowerPC的片上可编程系统,并且在定制的SOPC系统上移植了Linux系统,该Linux系统采用NFS的方式挂载文件系统。基于NFS文件系统的Linux的SOPC应用系统设计,很好地结合了SOPC和Linux系统的优点。采用NFS挂载方式的Linux文件系统也解决了以往SOPC平台上软件调试过程复杂和文件系统大小要求的限制。     

SOPC（片上可编程系统）：灵活、高效的解决之道

SOPC(System on a programmable chip:片上可编程系统)是Altera公司提出来的一种灵活、高效的解决方案,它将处理器、存储器、I/O口、LVDS、CDR等系统设计需要的东西集成到一个PLD器件上,构建成一个可编程的片上系统,它所具有的灵活性、低成本可让系统设计者获益非浅。 11月1日,Altera公司在北京举行了半天的研讨会,主要讨论了SOPC蕴含的技术,并展示了实践中构建的基于SOPC的系统。借这次会议机会,我采访了Altera公司中国区总经理赵典锋先生,请他详细介绍了SOPC的关键技术和应     

基于Nios Ⅱ的高速图像采集系统的设计

研究了一种基于SOPC技术的嵌入式高速图像采集控制系统的设计方案.该系统通过在FPGA芯片上配置NiosⅡ软核处理器和相关的接口模块来实现其主要硬件电路,并结合系统的软件设计来控制高速多功能视频解码芯片ADV7181和编码芯片ADV7123实现了图像的高速A/D、D/A转换、存储和回放等功能.由于采用了SOPC和DMA控制技术,该系统具有设计灵活、图像处理速度快和扩展性好等优点.     

基于FPGA的SOPC设计实践教学方法探索

基于FPGA的SOPC设计技术是现代电子系统设计人员的必备技能之一,并逐步成为嵌入式系统技术发展的新方向.本文针对电子科学与技术专业的教学实践,分别从SOPC嵌入式系统领域人才需求,知识体系进行分析.在此基础上,对课程内容,实验平台选择,实践环节设计和考核方式等进行了详细的说明,提出了一种基于Altera FPGA开发板DE2-70的SOPC设计教学实践体系.并以用户定制IP核实验为例,详细分析了该实践教学体系的教学效果.     

基于SOPC的汽车测距限速系统设计

为提高行车安全性,提出了一种基于SOPC技术的汽车激光测距限速系统。该系统利用单目标测距原理,可对前方车辆进行自动激光测距,依据不同车速所对应的不同安全距离完成声光报警及车速限制。最后在SOPC开发平台中进行设计,验证了该系统具备测距限速功能。     

基于SOPC的UART IP核设计与驱动开发及系统移植

设计基于SOPC嵌入式系统的UART IP核,依据UART协议,采用Verilog HDL进行各模块设计,使用ModelSim、Quartus II作仿真验证及综合,结果表明该UART IP核功能正确,稳定可靠。根据Avalon总线接口协议实现UART在系统总线上的挂载,建立SOPC嵌入式硬件系统,进行UART IP核驱动开发。利用超级终端实现嵌入式系统与上位机之间的通信,并成功移植uClinux操作系统,实现对嵌入式系统的高级控制。     

导航卫星接收机的SOPC设计

传统的接收机构成通常是由执行信号处理的可配置芯片(FPGA)加上执行软件调度的通用处理器(DSP,ARM)构成,需要通过两片芯片组合来完成接收机的功能。本文提出了一种导航卫星接收机的SOPC实现方法,把整个接收机的信号处理硬件和接收机软件系统集成到一片可配置芯片上来完成,实现小型化、低功耗、便携的SOPC接收机系统。本文的SOPC设计结果实现了一个功能完全的导航卫星接收机。     

网络化虚拟测控系统的设计

为满足计算机专业教学和测控仪器开发的需要,设计了基于网络、虚拟仪器和SOPC技术的网络化虚拟测控系统。该系统由PCI接口卡、基于NiosII软核的SOPC数据采集系统组成,使用Labview技术构建了C/S模式的远程数据采集和管理体系结构,并基于Windows DDK与VC++语言开发了PCI接口驱动程序。实际应用表明,该系统具有开放性、灵活性以及易用性等优点,达到了预期目的。     

基于SOPC的UARTIP核设计与驱动开发及系统移植

设计基于SOPC嵌入式系统的UARTIP核,依据UART协议,采用VerilogHDL进行各模块设计,使用ModelSim、QuartusII作仿真验证及综合,结果表明该UARTIP核功能正确,稳定可靠。根据Avalon总线接口协议实现UART在系统总线上的挂栽,建立SOPC嵌入式硬件系统,进行UARTIP核驱动开发。利用超级终端实现嵌入式系统与上位机之间的通信,并成功移植uClinux操作系统,实现对嵌入式系统的高级控制。     

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.     

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.     

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.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Influence of polarization extinction ratio on distributed polarization coupling detection

Distributed polarization coupling in polarization-maintaining fibers can be detected by using a white light Michelson interferometer. This technique usually requires that only one polarization mode is excited. However, in practical measurement, the injection polarization direction could not be exactly aligned to one of the principal axes of the PMF, so the influence of the polarization extinction ratio should be considered. Based on the polarization coupling theory, the influence of the incident polarization extinction on the measurement result is evaluated and analyzed, and a method for distributed polarization coupling detection is developed when both two orthogonal eigenmodes are excited.     

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes, analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation, and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system, The results indicate that the effects of noise in absorption region can be ignored; that with the increase of DC injecting current, the noise effects enhance power jitter, and nevertheless, the period jitter is decreased; and that with external sinusoidal current modulating the self-pulsation laser diode, the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.     

High-quality single-crystal CdSe nanoribbons and their optical properties

Large-scale synthesis of single-crystal CdSe nanoribbons is achieved by a modified thermal evaporation method, in which two-step-thermal-evaporation is used to control CdSe sources＇ evaporation. The synthesized CdSe nanoribbons are usually several micrometers in width, 50 nm in thickness, and tens to several hundred micrometers in length. Studies have shown that high-quality CdSe nanoribbons with regular shapes can be obtained by this method. Room-temperature photolumines-cence indicates that the lasing emission at 710 nm has been observed under optical pumping （266 nm） at power densities of 25-153 kW/cm^2. The full width half maximum （FWHM） of the lasing mode is 0.67 nm     

Propagation of hermite-cosh-gaussian beams passing through ABCD optical system with an annular aperture

By using the expansion of the aperture function into a finte sum of complex Gaussian functions, the corresponding analytical expressions of Hermite-cosh-Gaussian beams passing through annular apertured paraxially and symmetrically optical systems written in terms of ABCD matrix were derived, and they could reduce to the cases with squared aperture. In a similar way, the corresponding analytical expressions of cosh-Gaussian beams through annular apertured ABCD matrix were also given. The method could save more calculation time than that by using the diffraction integral formula directly.     

中国建立EB级存储实验室,致力云计算应用(英文)

正With the support of 863 programs,Sugon Information Industry Co.,Ltd.,set up a dawning EB-class storage laboratory to address massive data storage requirements and largescale cloud computing demonstration applications.The Dawning EB-class cloud storage system adopts advanced fault-tolerant architecture,efficient data fault-tolerant algorithms with user authentication and data encryption policies to deal with the"lost""wrong"and"stolen"problems of data for ensuring the reliability and safety of the EB-class storage system in the public network application environments.The Dawning EB-class Storage Laboratory taking advan-