适应数字信号处理应用需求的DSP系统软件设计

该文仔细分析了控制系统和信号处理系统对实时操作系统(RTOS)的不同需求,从而得出结论,认为降低对实时操作系统软件的要求,就可以设计出同时兼顾了软件运行效率和软件开发效率,并且适应信号处理系统需求系统软件。该文所提方法在实践中加以实施并获得一定效果。     

分布式服务架构在信号处理系统中的应用

随着软件无线电技术的兴起,信号处理系统的可移植性和可重用性得到了很大提升。然而,组件化设计不可避免地会增加系统设计复杂度、降低系统运行效率。为了简化组件设计,提高系统开发及运行效率,满足快速搭建原型系统的需求,提出了一种基于服务架构的信号处理系统模型。模型基于ICE中间件技术,解决了Matlab程序快速服务封装和多线程服务调用等关键技术。通过将该架构模型应用于实际的软件无线电系统,验证了其可行性。实验结果表明,该框架具有良好的扩展性,提高了系统性能。     

海量数据处理系统设计的几点探讨

文中针对海量数据的处理,结合Oracle数据库设计的实践,就数据库设计中的表设计、数据装载、查询,资源优化等内容进行了探索,在提高大型数据库运行效率方面提出了比较切实可行的思路和方法。     

红黑树优化的SQLite索引在测速系统中的应用

针对当前以B树为存储结构的SQLite数据库在处理庞大数据量时效率低下的问题,使用红黑树结构来替换B树结构,并将经红黑树优化过的SQLite应用在交通监控测速仪系统上。首先在Visual Studio 2008环境下分别运行红黑树及B树代码,对随机产生的大量数据执行插入、查询及删除操作,并将上述操作的时间开销进行对比分析;然后将优化的SQLite应用在交通监控测速仪系统中,并同使用原SQLite的同型号设备就处理数据的效率进行对比分析与测试。结果表明,在处理庞大数据时,红黑树对数据的操作效率要远高于B树,当数据量同为600万条时,其插入、查询和删除操作的平均时间开销分别降低68.5%,84.4%和68.8%;同原交通监控测速仪相比,使用经红黑树优化的设备效率提高了40.16%。     

数据传输终端设备的时延性能优化

数据信号的处理和传输是无线数字通信系统中的重要环节.针对数据信号处理和传输的实时性需求,以Windows平台下采用软件无线电技术设计的数据传输终端设备为例,详细分析了数据信号在实时数据传输中时延性能问题,根据应用软件、DSP嵌入式软件和FPGA设计和实现特点,提出具体、有效的优化措施,包括任务调度机制、线程同步技术、DSP存储算法及FPGA数据采集策略.测试结果和工程实践表明,采取的措施取得了较好的优化效果.     

核心技术在这里

本月精彩文章推荐通过LabVIEW优化多核处理器信号处理性能http://www.ednchina.com/1009-001.aspx作为一种并行结构的编程语言,LabVIEW能将多个并列的程序分支自动分配成多个线程并分派到各个处理核上,让一些计算量较大的数学运算或信号处理应用得以提高运行效率,并获取最佳性能。     

考虑数据完整性的数字化电网中台优化系统

为了有效提高系统信噪比和运行效率，加快信息发送速率，确保系统运行稳定性，设计考虑数据完整性的数字化电网中台优化系统。根据信息自适应控制逻辑，设计自适应优化电路；通过分析数字化电网中台数据，利用隐含攻击路径，找出相同中台数据中的已知漏洞信息；计算数据漏洞的利用率，结合自适应性优化流程，实现数字化电网中台优化。测试结果表明，该系统的信噪比和运行效率较高，中台信息发送速率较快，能够有效确保系统运行稳定性。     

基于ADSP TS201的雷达通用信号处理板的设计

为了缩短信号处理系统的研发周期,需要一个通用的信号处理硬件平台,只通过设计软件就可以满足不同雷达系统的需求。采用高性能DSP和FPGA为主要芯片设计通用信号处理板,多片DSP通过链路口及总线共享的方式,可以同时进行数据的交互和处理,运算能力强。 FPGA与DSP之间也具有链路口及总线通道,可以将多种接口形式的数据通过转换与DSP进行数据交换。 DSP和FPGA相结合既满足了信号处理的数据处理能力,又拥有多种数据接口方式,适合不同雷达系统信号处理的应用,具有一定的通用性。     

CCD遥感相机视频电子系统FPGA软件集成化设计

为满足CCD遥感相机视频电子系统集成化、小型化的需求,提出一种FPGA软件集成化设计方法,将传统视频电子系统中焦平面软件、信号处理软件和积分时间软件三部分软件集成在一片FPGA中。通过软件模块标准化使软件结构更加优化,可靠性更高。实际应用表明,该软件集成化设计能够实现焦平面软件、信号处理软件和积分时间软件的全部功能,简化了硬件电路的同时提高了软件集成度,具有很高的工程应用价值。     

CAMALOT点胶机离线编程系统——CPS的设计与开发

SMT设备要达到最大的产量,必须要考虑生产线的效率。点胶机是SMT生产线中的重要设备,因此提高点胶机的生产效率具有十分重要的意义。文章以CAMALOT5000系统为例,介绍了点胶机离线编程软件的设计与开发中的思想、方法和经验,并着重探讨了坐标数据的处理和转换,同时针对基于点胶系统优化的TSP问题进行了分析和研究,对程序优化进行了系统分析设计,并编程实现了基本方案。最后在CAMALOT5000系统上使用本解决方案,大幅度提高了生产效率,证明了本解决方案的优越性和高效性,也为其它SMT设备的离线编程软件的设计提供了一种可参考的思路。     

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.     

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.     

Technology innovation and process integrations for sub-100nm gate patterning

This paper presents a brief overview of the Applied Centura(R)DPS(R)system,configured with silicon etch DPS Ⅱ chamber, with emphasis on discussing tuning capability for CD uniformity control. It also presents the studies of etch process chemistry and film integration impact for an overall successful gate patterning development. Discussions will focus on resolutions to key issues, such as CD uniformity, line-edge roughness, and multilayer film etching integration.     

White organic light-emitting devices based on fac tris（2- phenylpyridine） iridium sensitized 5,6,11,12-tetraphenylnap -hthacene

We have fabricated the white organic light-emitting devices （WOLEDs） based on 4,4＇ -bis（2,2 -diphenyl vinyl）-1,1＇ - biphenyl （DPVBi） and phosphorescence sensitized 5,6,11,12,-tetraphenylnaphthacene （rubrene）. The device structure is ITO/2T-NATA （20 nm）/NPBX （20 nm）/CBP： x%Ir（ppy）3：0.5% rubrene （8 nm）/NPBX （5 nm）/DPVBi （30 nm）/Alq（30 nm）/LiF（0.5 nm）/A1. In the devices, DPVBi acts as a blue light-emitting layer, the rubrene is sensitized by a phosphorescent material, fac tris （2-phenylpyridine） iridium [Ir（ppy）3], acts as a yellow light-emitting layer, and N,N＇ -bis- （1-naphthyl）- N,N＇ -diphenyl -1, 1＇ -biphenyl-4,4＇ -diamine （NPBX） acts as a hole transporting and exciton blocker layer, respectively. When the concentration of Ir （PPY）3 is 6wt%, the maximum luminance is 24960 cd/m^2 at an applied voltage of 15 V, and the maximum luminous efficiency is 5.17 cd/A at an applied voltage of 8 V.     

Complete approach to automatic identification and subpixel center location for ellipse feature

To meet the need of automatic image features extraction with high precision in visual inspection, a complete approach to automatic identification and sub-pixel center location for similar-ellipse feature is proposed. In the method, the feature area is identified automatically based on the edge attribute, and the sub-pixel center location is accomplished with the leastsquare algorithm. It shows that the method is valid, practical, and has high precision by experiment. Meanwhile this method can meet the need of instrumentation of visual inspection because of easy realization and without man-machine interaction.     

小角度扩展相关性近似算法分析

本论文提出一种在多天线MIMO信道相关性建模中小角度扩展近似理论算法,并应用于分析MIMO系统性能。分析中分别对三种不同角能量分布情况下的空间相关性研发快速近似计算法,并同时提出双模(Bi-Modal)角能量分布情况下的近似运算。通过分析这些新方法的近似效率,可以得到计算简单、复杂度低、而且符合实际的MIMO相关信道矩阵,对系统级的快速高效计算法的研究和系统级的评估以及误差分析具有重要的意义。     

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.