基于Miron NAND Flash的弹载数据记录器的设计

为解决传统以三星NAND Flash为基础的弹载数据记录器存储容量有限、存储速度难以提升的问题,以兼容ONFI2.2协议的MT29F32G08ABAAA为存储芯片,采用高效流水线操作以及无效块管理的逻辑设计,对芯片工作模式进行合理配置,设计了新一代数据记录器;介绍了该记录器的工作特性、能够满足特殊环境要求的硬件设计和基于高效流水线操作以及无效块管理的高速逻辑设计,最终实现了写入速度为56 MB/s、存储容量为4 G的高速大容量数据记录器。     

USB3.0接口在数据存储系统中的应用

USB3.0的传输速率最快可达5Gbps,因此,为实现大量数据的快速稳定传输,介绍了一种以FPGA为控制核心,DDR2 SDRAM为高速大容量缓存,USB3.0为记录器与计算机进行数据通信接口的高速数据传输系统,通过模块硬件电路及软件协议实现了数据的高可靠性稳定传输,解决了大容量记录器的数据传输速度瓶颈。经长期试验证明：该接口传输速度可稳定到达150M/s,且数据可靠无误,满足任务设计要求。     

双通道高速数据采集处理平台的设计与实现

为满足数字式测向接收机对高速数据采集和处理的需求,研制了高速数据采集处理平台,该平台基于ADC12D1800RF模数转换器实现了两路1.35GHz中频信号的带通采样,以Xilinx公司V7系列FPGA为数据处理器,采用高速DDR3作为存储设备解决了海量数据存储问题,并通过高速串行接口（GTX/SRIO）实现了大容量数据的实时传输。该平台的测试结果为：1.8GHz采样率时有效位数大于8bit,DDR3存储器的工作主频可达1333MHz,GTX接口在10Gbps速率下工作时,其误码率小于10-9,上述测试结果表明该平台可以高速、准确地实现信号采集、数据传输、存储和处理,达到了预期设计目标。     

空间雷电探测实时采集定位系统

星载雷电探测定位系统是利用光学探测器探测闪电事件的地理位置和光脉冲波形，系统采用CPLD+DSP的数字图像处理方案，利用了CPLD复杂逻辑可编程特性将系统的部分或全部功能集成在一片CPLD上，减小了系统硬件复杂程度，节省了印制版空间.利用DSP高速数字信号处理特性完成实时处理图像数据的功能.系统用CPLD完成图像信号的采集、编码和存储控制,缩小了星载设备体积，简化了电路结构；用DSP完成大量图像数据处理工作，提高了系统工作的实时性.     

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。     

基于CH378的便携式高速数据采集系统设计与实现

针对数据采集系统在速度、容量和体积方面的需求,文中提出了一种基于FPGA的便携式高速数据采集系统方案,采用可充电锂电池作为供电电源,采用FPGA控制读写大容量Flash数据作为高速数据缓冲,控制USB接口芯片CH378完成对U盘的读写操作,实现大容量数据的可靠和便携存储;详细介绍了该测试系统的设计背景、硬件电路的设计依据、固件程序的设计思想和测试系统的具体实现;实验结果表明,该系统具有成本低、通用性强、可靠性高、便携式操作等优点,能够实现数据的高速采集,海量存储,实现了脱离计算机直接存储数据至U盘的功能。     

基于FPGA高速数据采集与存储系统的设计

对高速数据采集系统进行了研究,基于其采集速率的问题,提出了一种基于FPGA的高速数据采集系统。利用FPGA实现对12bit的A/D转换器ADC12D800的控制,使用其1.6Gsps双沿采样工作模式完成对400MHz以下高频信号的数据采集。通过设计数据存储方式来降低数据传输速率,使数据经USB传至PC机来实现高频信号地实时采集与存储。实验结果表明它可以实时、高效地完成数据采集,可以应用到雷达、通信、电子对抗等领域。     

多通道高速信号的同步采集和处理

一种采用直接存储方式完成多通道高速信号并行采集的多通道高速信号同步采集器，采用直接存储方式，数据不需要经过CPU“中转”，直接将采集的数据写入数据存储器中，而CPU的主要任务是读取存储器数据和与上位机的通讯，多通道高速信号同步采集器通过RS-232/RS-485A方式与上位机通讯，构成多通道高速信号同步采集系统。     

一种高速CCD视频实时存储方案的速度分析

为了满足高帧频、大面阵CCD数字视频实时存储要求,在分析数字视频的信号特点和SCSI系统数据传输过程的基础上,建立了缓冲并行预处理和SCSI直接存储阵列数据传输的理论模型。从理论和实验两个方面分析了SC SI总线速度和SCSI硬盘持续存储速率两个决定存储速率的主要因素,并且分析了数据分块大小,LBA(逻辑块地址)范围以及系统调度策略对SCSI硬盘阵列数据存储速度的影响。实验表明,通过选择合适的应用背景来减少总线冲突,可以满足100MB/s视频数据的存储要求。     

高速CCD图像数据存储技术

介绍了一种高速CCD图像数据的实时存储方法利用FIFO缓存器使CCD输出的高速数据流和低速存储介质二者的速度匹配,将多路高速大容量图像数据实时记录到了存储介质中,为后期的图像恢复和图像处理提供了原始数据该图像数据存储的方法对各种数据采集以及存储系统的设计具有很好的参考意义.     

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.     

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.     

Theoretical analysis and simulation of conjugate heights for dual-conjugate AO system in lidar

A multi-conjugate adaptive optics （MCAO） can offer a possibility of widening field of view （FOV） characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle＇s expressions of two deformable mirrors （DMs） MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance.     

Quick single-photon detector with many avalanche photo diodes working on the time division

Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system.A new idea is put up to design a quick single-photon detector.This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs).Au of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal.The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector.The single-photon prompt detection can come true for high repetition-rate pulses.The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use.     

Improvement of four-wave mixing-based wavelength conversion efficiency in dispersion shifted fiber by 40-GHz clock pumping

40-GHz clock modulated signal as a pump to improve the efficiency of four-wave mixing (FWM)-based wavelength conversion in a 26.5-km dispersion shifted fiber (DSF) is investigated. The experimental results demonstrate that the conjugated FWM component has higher intensity with the clock pumping than that with the continuous-wave (CW) light pumping. The improvement of FWM-based wavelength conversion efficiency is negligible when the pump power is less than Brillouin threshold. But when the pump power is greater than Brillouin threshold, the improvement becomes significant and increases with the increment of pump power. The improvement can increase up to 9 dB if pump power reaches 17 dBm.     

Characterization of PolyA and PolyC mismatches by Raman spectroscopy

A.C mismatches are studied by Raman spectral characterization of PolyA, PolyC, and their equimolar complex in solution of 0.14 mol/L Na ,pH7.0.Experimental results show that A·C mismatches occur to be A/B (mainly A) conformers, and unlike Watson-Crick base pairing, this kind of mismatches is stabilized by only one hydrogen bond involving cytosine N4H2 and adenine N7.The formation of A·C complex makes the base stacking interactions much stronger, and conformation of the backbone more ordered, which leads to obvious Raman hypochromic effect with some shifts in corresponding bands.     

Speech enhancement by array crosstalk resistant ANC and spectrum subtraction

Microphone array-based speech enhancement has great importance for speech communications and speech recognition. To reduce the aperture of the microphone array and to increase the effect of the speech enhancement will greatly broaden the application areas of the microphone array. An array crosstalk resistant adaptive noise cancellation method is therefore presented. And then an improved spectral subtraction algorithm is further cascaded to obtain better enhancement results. Theoretic analysis and experiments indicate that the proposed scheme needs only a very small microphone array while it simultaneously achieves a higher SNR improvement. Besides, the proposed scheme can be used in many noisy environments and is easy for real-time implementation.     

Multi-pulse operation of a Kerr-lens mode-locked femtosecond laser

Our experimental results show that the presence of a proper amount of negative group velocity dispersion is essential to multi-pulse operation of a Kerr-lens mode-locked femtosecond laser. We demonstrate that the pulse separations and the number of pulses contained within a cavity round trip are strongly dependent on the initial perturbations. The results allow us to get a better understanding on the influences of the convoluted self-phase modulation and intra-cavity dispersions on the stable multi-pulse oscillation in a Kerr-lens mode-locked femtosecond laser.     

Propagation of Helmholtz-Gauss beams in weak turbulent atmosphere

Based on the Rytov approximation of light propagation in weak turbulent atmosphere,the closed-form expressions of field and average irradiance of each one of the four fundamental families of Helmholtz-Gauss (HzG)beams:cosine-Gauss beams,stationary Mathieu-Gauss beams,stationary parabolic-Gauss beams,and Bessel-Gauss beams,which are propagating in weak turbulent atmosphere,are obtained.The results show that the field and average irradiance can be written as the product of four factors:complex amplitude depending on the z-coordinate only,a Ganssian beam.a factor of complex phase perturbation induced by atmospheric turbulence,and a complex scaled version of the transverse shape of the non-diffracting beam.The effect of weak atmospheric turbulence on irradiance distribution of the HzG beam can be ignored.