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针对某新型机载视频测试需求的迫切性以及目前测试方法和设备不能满足试飞测试需求的问题,以TMS320DM6467T芯片为核心处理单元,采用FPGA和DSP设计技术,完成了机载高清VGA视频采集系统的硬件和软件设计,成功解决了该型机载视频的采集与处理,实现了对该机专用视频采集各要求项目的自动测试功能和自检功能;该视频采集系统已成功得到应用;实践表明,该系统能够满足测试需求,具有测试精度高、运行稳定、可扩展性好等特点。 相似文献
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在飞行试验中,机载ARINC429总线往往包含重要的试飞数据,采集ARINC429总线是试飞测试系统中重要的一环。以往的ARINC429总线采集技术,一般采用分离元器件构成,造成电路体积大、功耗大,可靠性降低。在新一代网络化采集器创新性预研背景下,提出了一种基于DSP和FPGA架构的通用设计方案,FPGA进行总线协议解析,DSP进行数据的筛选,充分发挥出FPGA的并行优势和DSP的灵活特性。同时,设计了数据采样和传递机制,并在实际工程中得到应用。 相似文献
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介绍一种机载飞控系统飞控计算机对各种控制信息(包括离散量、模拟量和串行数据)进行数字化控制、实时采集、监控和处理的接口模块设计方法,从工程应用角度出发,阐述了模块的设计思路以及工程实现,给出原理框图和测试流程。在某型飞机的实际应用中,实现了32路离散量输入输出、16路模拟量输入输出、6路ARINC429串行数据收发、4路ARINC422串行数据收发以及4路ARINC232串行数据收发的功能,自测试覆盖率达100%。因该模块的接口形式和接口数量可根据实际需要进行增减,故具有很强的典型性和通用性,可适用于各类型的机载飞控系统。 相似文献
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航空机载测量数据采集是一种长时间、高效率数据采集过程,需要完成机载任务单元多通道数据的不间断采集,传统的机载测量数据采集系统需要进行多次断电和重新上电工作,不能丢失通电条件下保存的数据,一旦机载任务单元通道突然断电,导致通电条件下数据大量丢失,无法完成机载测量数据的准确采集;设计了一种基于QNX SDP的机载测量数据采集系统,分析了系统硬件数字电路和模拟电路的抗干扰设计,系统软件由采集初始化模块、数据采集模块以及QNX SDP系统时钟定时模块构成,3个模块通过QNX SDP进程管理器基于优先级进行合理调控,分析了基于QNX SDP的PWU人机界面模块组成和主要实现的任务,实现了用户和系统的实时机载测量数据交互;实验结果说明,所设计系统可实现ARINC429机载测量数据的有效采集,并给出ARINC429数据波形图,该系统具有较低的花费、较高的采集效率和精度,在机载测量数据实时采集应用中具有较好的通用性和扩展性。 相似文献
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针对飞行器搭载相机视频存储和传输的需求,设计了一种基于异构多核处理器DM8168的小型机载视频记录仪。首先,基于DM8168和FPGA处理器设计小型化低功耗的硬件系统;接着,基于McFW软件架构设计视频采集编码的数据流,充分发挥DM8168多核体系结构的优势,实现两路1080P60视频的采集,并且对每路视频分别进行主次码流的H.264编码;最后,采用GPMC总线,将视频码流传输到FPGA处理器,以实现本地视频存储和远程视频传输。本记录仪体积小功耗低、记录时间长、视频传输时延小,能够很好地满足飞行器多路视频记录的需求。 相似文献
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飞行试验是对飞机的性能进行验证和确认的关键阶段,试飞测试是保障该阶段工作的重要内容;国内目前对于军机已拥有了成熟的测试技术、测试方法和可靠的测试设备,而对于民用飞机特别是大型民机的试飞测试目前还处在起步阶段;随着国家大飞机研制专项的不断推近,大型客机试飞测试需求逐步明确;从大型民机试飞测试需求和测试工作特点出发,对机载测试技术变革、遥测和数据处理技术等键技术在国外的最新发展和国内大型飞机的现状进行对比分析,可以看出我国民机试飞测试在网络化机载测试系统应用、遥测传输链路带宽、大数据快速处理等方面存在较大的挑战;在此基础上对应对挑战的发展策略和后续攻关的方向进行研究,可以为我国大型飞机特别是民机试飞测试技术的发展提供参考。 相似文献
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为了解决飞行试验测试系统跨代升级,网络化测试系统采集记录的多源iNET试飞数据的精密分析难题,针对新形势下的网络化测试系统应用于飞行试验所特有的多源数据测试技术架构,分析了该测试技术架构的特点,以及精密分析对试飞工程师验证测试系统同步采集及数据同步分析算法的重要性,提出了基于数据流StreamID的测试参数iNET精密分析方法及实现技术,实现了多源iNET试验数据的精密分析;最后在采用了网络化测试系统的某试验机的飞行试验中对多源iNET数据进行了精密分析,试验表明使用这些算法的数据处理软件满足飞行试验iNET精密分析的需求。 相似文献
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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. 相似文献
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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. 相似文献
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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. 相似文献
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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. 相似文献
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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. 相似文献
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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. 相似文献
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Xin Kang 《中国光学快报(英文版)》2008,6(2)
An effective method for reducing the speckle noise in digital holography is proposed in this paper.Different from the methods based on classical filtering technique,it utilizes the multiple holograms which are generated by rotating the illuminating light continuously.The intensity images reconstructed by a series of holograms generated by rotating the illuminating light possess different speckle patterns.Hence by properly averaging the reconstructed intensity fields,the speckle noises can be reduced greatly.Experimental results show that the proposed method is simple and effective to reduce speckle noise in digital holography. 相似文献
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The impurities in two kinds of HfO2 materials and in their corresponding single layer thin films were determined through glow discharge mass spectrum technology and secondary ion mass spectrometry(SIMS) equipment respectively.It was found that ZrO2 was the main impurity in the two kinds of HfO2 either in the original HfO2 materials or in the electron beam deposited films.In addition,the difference of Zr content in the two kinds of HfO2 single laver films was much laxger than that of the other impurities such as Ti and Fe.which showed that it was just ZrO2 that made the difference between the optical performance of the film products including the two kinds of HfO2.With these two kinds of HfO2 and the same kind of SiO2.we deposited HfO2/SiO2 multilayer reflective coatings at the wavelength of 266 nm.Experimental results showed that the reflectances of these two mirrors were about 99.85% and 99.15% respectively,which agreed well with the designed results what were based on the optical constants obtained from the corresponding single layer thin films. 相似文献
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References: 《声学学报:英文版》2008,27(1):85-96
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. 相似文献