基于VME总线的高速信号处理模块测试技术研究及应用

为解决某型号炮位侦察校射雷达中高速信号处理模块的测试,文中设计了基于VME总线的高速数字电路自动测试系统,该系统能模拟雷达工作环境,利用VME测试模块提供测试所需的光口、RapidIO等信号,测试结果通过VME主控器网口上报给系统管理平台;该系统成功应用于某型雷达高速信号处理模块的测试,可完成VME总线接口的测试;3路RapidIO信号的测试,Rapid IO信号传输速率为3.125 Gbps;4路光纤通道的测试,光纤通道波特率为2 Gbps;研究及实测结果表明该系统可解决基于VME总线的高速信号处理模块的测试。     

基于VXI总线的四路门控积分器模件的研制

 介绍了一个基于标准总线VXI的四路门控积分器模块插件。在四路独立的纳秒门控积分电路的基础上,采用VXI寄存器基接口实现对各路门控积分器的数据采集和控制,采用Labwindows/CVI编写了数据采集系统软件,从而完成了纳秒级门控积分器的实用化的基本工作。电子学测试结果和现场打靶结果表明该系统完全符合实用系统的要求。     

基于ATEasy的通用射频测试系统研究与实现

针对引进现代电子装备及系统中射频模块故障频发的问题,为实现对引进电子装备及系统射频模块的自动测试及故障诊断,达到降低外送维修成本、缩短维修周期、提高维修效率等目的,研制通用射频测试系统。通用射频测试系统硬件基于GPIB及VXI总线技术集成精密测试仪器仪表实现,利用VXI矩阵开关构建模块串并回路,设计系统通用接口适配器,提出自动测试射频模块工作电流及电压的电路设计;软件架构及测试程序采用美国GEOTest公司的ATEasy8.0。目前基于ATEasy集成开发环境开发射频模块测试程序,已实现20余种射频模块的自动测试及故障诊断。经验证,测试结果有效。该系统为引进现代电子装备及系统射频模块的测试开辟新的途径,提供新的支持。     

用于精密位移测量的微型光栅传感器开发

基于双光栅干涉扫描原理,通过复用透射光栅实现干涉扫描型光栅位移传感器的小型化开发。开发了适用于精密位移测量的光栅传感器原理样机。传感器的电路系统包括信号转换放大电路模块和置于传感器D-SUB接口外壳内的信号处理电路模块。通过15 pin接口输出四路电平为2.5±0.5 V的模拟差分信号,差分信号接口可用于高倍细分而达到高分辨率,具备RS422接口适配能力,可以提高传感器远距离传输的抗干扰能力。以电容传感器为基准,光栅位移传感器原理样机实现了±30 nm的重复性精度,满足10 mm/s的测量速度需求,10 s短时位移稳定性达到5 nm,6 h的长时间稳定性达到70 nm。     

飞行器遥测设备与综控机一体化设计

随着新一代飞行器技术的快速发展,对其体积、航程以及信息化程度的要求越来越严格。为此,提出了飞行器遥测设备与综控机的一体化设计,利用的数据监测与处理模块替代传统飞行器上单独的遥测设备,将其集成到综控机当中,大大节约了飞行器空间,提高了其信息处理与监测能力。该模块基于NandFlash存储器、DSP/BIOS实时操作系统千兆以太网接口以及PCM接口,能够实现大量数据的实时存储与传输。经大量试验证明：NandFlash存储器能够可靠的记录大量实验数据,千兆以太网接口可以很好的实现飞行器系统与测试设备之间的高速数据传输,通过PCM接口能够组织完成遥测数据的实时发送,既具备传统遥测设备的功能,又提高了数据处理、存储与监测的能力。     

基于新型ICP脉动压力传感器的信号调理电路设计与实现

在飞行器地面试验中,新型ICP脉动压力传感器常用来测量飞行器与发射筒之间的关键位置表面由于空气脉动产生的脉动压力参数;ICP脉动压力传感器工作时需要恒流源供电,同时其输出信号不能满足大多数模数转换芯片对于输入电压的要求,针对以上问题,提出了一种基于新型ICP脉动压力传感器的信号调理电路,并详细介绍了电源电路、脉动压力信号调理电路等模块的设计原理和方法;测试结果表明该设计能够满足新型ICP脉动压力传感器3.4 mA恒流源供电需求,并且能准确地将其输出电压信号调理为0.366~2.13 V,符合AD7667转换范围要求,同时能有效地滤除信号中混入的9.6 kHz以上的高频噪声以及椭圆型高阶低通滤波器自身引入的开关噪声;该信号调理电路可靠性高,已经成功应用于飞行器地面发射试验中。     

基于CPLD的多路瞬态冲击信号存储测试系统设计

为了对水平碰撞、跌落等环境试验中的多路瞬态冲击信号进行测试,基于CPLD设计了多路瞬态冲击信号嵌入式存储测试系统。系统采用高速串行AD转换芯片作为数据采集的执行器件,实现了多路冲击信号的同步高速采集;利用铁电存储器对采集到的信号进行在线存储;设计了USB接口模块,实现了PC机与测试系统之间的通信,并在LABVIEW环境下设计了数据回读软件;经试验验证了测试系统的正确性和可靠性。     

采用可编程I/O接口的多路串行通讯模拟器设计

某航天器闭式贮箱增压控制系统的测试中,需要设计具有多路串行通讯接口的模拟器,用于模拟数字式压力传感器的输出信号。对于72路串行发送和10路串行接收功能,若采用传统商用的标准串行通讯接口板,则整个模拟器需要十多套板卡,系统复杂,体积大,且多个通道之间难以实现同步与实时控制。为此提出了一种采用多路可编程I/O接口板实现485通讯功能的方案,借助于LabVIEW软件开发平台,由FPGA编程实现通讯协议;并配置信号调理板以实现信号的隔离传输和驱动。最终仅用一台小型便携式设备和三块板卡就实现了模拟器的所有功能,可以灵活地根据系统设置的工作模式模拟传感器的输出,在增压系统的测试中表现优异。试验结果表明,此种设计方案具有较强的通用性和适应性,可以广泛推广到多种通讯应用场合。     

一种压力传感器单故障实时诊断方法研究

研究对象为容式变极距型液位压力传感器。分析了传感器测量电路的工作原理与特性。故障诊断首先用压力变化率判断测量电路故障存在性;再得到额定输入信号下电路电桥输出信号和运算放大器输出这两个检测信号的表达式,各表达式均以电路相关元件为自变量。因不同元件发生数值漂移故障时,对检测信号的影响趋势各不相同,使得精确到元件的故障定位得以实现;确定故障位置后将正常元件值代入检测信号表达式联立方程组求解,以实现精确到元件的故障定值。仿真显示该故障诊断方法所求得故障值非常接近真实故障值。     

PSM高压电源系统模块的计算分析

在低杂波高压电源系统的整流模块的研究中,对含有LC滤波的三相不控整流电路的输出电压进行分析计算,得到输出电压与电路中的参数关系表达式.通过MATLAB/Simulink模块中的电路仿真元件对三相不控整流电路进行仿真,得到其输出电压的波形图,观察得到其输出波形能够满足电源系统的设计要求.     

Hybrid Wavelength and Code Division Multiple Access in Optical Networks

A review of schemes for multiple access in fiber optic networks shows that a hybrid of wavelength and code division multiple access (WCDMA) combines the best features of both. In particular, the hybrid scheme retains the large information carrying capacity of wavelength division multiple access (WDMA) and flexibility of code division multiple access (CDMA). In this paper WDMA, optical CDMA (OCDMA), and WCDMA networks are discussed. In OCDMA networks, concept of incoherent and coherent coding including inverse decoding and matched filter is introduced. The delay performance of both WDMA and WCDMA networks, under the simple suboptimum access protocols based on cyclic search, is computed. It has been shown quantitatively that tuning delay significantly affects the delay performance of both WDMA and WCDMA networks. Futhermore, delay performance of WCDMA networks is always better than the WDMA networks for the same tuning delay, load, and number of users.     

Guided-Wave Two-Dimensional Acousto-Optic Scanner Using Proton-Exchanged Lithium Niobate Waveguide

Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs.     

Femtosecond Transform-Limited Pulse Generation by Compensating for the Linear Chirp of SPM Spectra in Dispersion Shifted Fibers

A simple technique of pulse compression, based on the linear chirp compensation of self-phase modulation (SPM) spectra in dispersion shifted fibers, is demonstrated. The optimization procedure is carried out, for a short span of a single-mode fiber, using a parabolic law, which describes the behavior of the squared output pulse width versus the pump peak power in the case of Gaussian pulses. The experimental results give a minimum pulse duration of 233 fs, which is in good agreement with the model. Shorter and coherent pulses, down to 90 fs, have been obtained by inserting an interference filter at the optical output.     

Effect ofγ-radiation on the spectral luminescence characteristics of impure cadmium tungstate crystals

Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·10⁴ Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.     

Research on beamforming method for dual-line array with space mismatch between the two line arrays

The performance of port/starboard discrimination of dual-line array will be seriously degraded when the space between the two line arrays of the dual-line array is mismatched. The directivity function of the delay-sum and delay-subtract beamforming is deduced and the port/starboard discrimination of the delay-sum and delay-subtract beamforming is also studied both under the ideal status and the status under which the space between the two line arrays of the dual-line array is mismatched. Analysis results show the delay-subtract beamforming has better performance of port/starboard discrimination. At last, the sea trial results demonstrate the theoretical results.     

Sorting of bending magnets for the SSRF booster

The Shanghai Synchrotron Radiation Facility(SSRF)booster ring,a full energy injector for the storage ring,is deigned to accelerate the electron beam energy from 150MeV to 3.5GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping.Closed orbit distortion(COD)caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting.Considering the affections of random errors in measurement,both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5is given as the final installation sequence of the booster bending magnets in this paper.     

Retrieval of ultraviolet skylight radiances and O3 slant column densities from balloon-borne limb spectrometer

With a novel light-weight and absolutely calibrated ultraviolet （UV） spectrometer, UV skylight radiances and O3 slant column densities are measured by balloon-borne limb measurements in Xinjiang area, China. UV skylight radiances measured at the height of 31 km are compared with the results from Modtran in the wavelength range from 290 to 420 nm. O3 slant column densities are derived from radiance spectra in the Huggins bands （320 - 335 nm） using differential optical absorption spectroscopy method. And the parameter exhibits a good correlation with the same value simulated by radiative transfer model （Tracy）. The O3 profile simultaneously measured by an O3 sonde is used as input in Tracy calculations. The O3 sonde is launched on the same balloon.     

Design optimization of highly sensitive LSPR enhanced surface plasmon resonance biosensors with nanoholes

For breaking through the sensitivity limitation of conventional surface plasmon resonance (SPR) biosensors, novel highly sensitive SPR biosensors with Au nanoparticles and nanogratings enhancement have been proposed recently.But in practice, these structures have obvious disadvantages.In this study, a nanohole based sensitivity enhancement SPR biosensor is proposed and the influence of different structural parameters on the performance is investigated by using rigorous coupled wave analysis (RCWA).Electromagnetic field distributions around the nanohole are also given out to directly explain the performance difference for various structural parameters.The results indicate that significant sensitivity increase is associated with localized surface plasmons (LSPs) excitation mediated by nanoholes.Except to outcome the weakness of other LSP based biosensors, larger resonance angle shift, reflectance amplitude, and sharper SPR curves' width are obtained simultaneously under optimized structural parameters.     

Polymer gratings based on photopolymerization for low-order distributed feedback polymer lasers

Novel polymer distributed feedback(DFB)gratings are fabricated based on photopolymerization to reduce lasing threshold of polymer lasers.A photopolymer formulation sensitive to 355-nm ultraviolet(UV)light is proposed for the fabrication of polymer gratings and it can be used to form polymer films by spin-coating process.A very low surface-relief depth ranging from 12.5 to about 1.0 nm has been demonstrated with a refractive-index modulation of about 0.012.The experimental results indicate that such polymer gratings have promising potentials for the fabrication of low-order DFB organic semiconductor lasers.     

A novel methodology for photometric compensation of projection display on patterned screen

We propose a novel methodology based on the projector-camera (ProCam) system to address the photometric compensation issue for the projection display on the patterned screen.The patterned screen is treated as the combination of a perfect white screen and a color modulator.The perfect white screen is used to automatically and accurately characterize the ProCam system offline using the polynomial model,and the parameters of the color modulator can be efficiently recovered by employing only two gray images based on the linear reflectance model.The experimental results show that the color artifacts of the display image can be greatly improved with this methodology,which demonstrates its feasibility and validity in the photometric compensation.