激光测距回波信号高速采样处理技术研究

激光脉冲测距中,微弱回波信号的检测处理一直是一个难题.随着测距指标的提高,直接提取回波转换电平的方法已无法满足测距精度和测程的要求.本文针对激光回波信号信噪比较低时,如信号的脉宽较窄、幅值较小时,利用高速AD采样技术,结合FPGA的高速信号处理能力,设计了一套回波检测处理系统,以期提高对回波信号的拾取精度和较为精确的计...     

Nd:YAG脉冲激光测距及应用研究

Nd:YAG脉冲激光测距技术在军事和民用方面都有广泛的应用。与其他测距方法相比,Nd:YAG激光测距技术具有明显的优越性。介绍Nd:YAG激光测距的基本原理、脉冲激光器的种类和常见的脉冲激光测距方法等。     

自适应多目标图像跟踪处理系统研究

针对空间多目标跟踪测量,介绍一种应用于武器试验的多目标图像跟踪处理系统。通过分析多目标自适应数字"波门"识别技术的综合预测算法,建立多"波门"系统捕获和跟踪方案,实现对多目标的选择跟踪。同步过程采用高精度数字锁相,增加测量精度。该系统在多目标跟踪测量中具有较广的应用前景。     

核磁共振测井信号调理与回波提取技术研究

针对核磁共振激励发射信号CPMG序列的特点,采用一种微弱信号调理技术对核磁共振回波信号进行预处理以便于回波信号的提取,并提出了一种相敏检波算法以提取相应的微弱回波信号.信号接收调理电路设计采取了隔离板与前置放大板配合协调工作,以达到防止高压发射信号冲击和微弱信号调理的作用.目前已经利用该信号调理技术与DPSD算法成功提取出相应的核磁共振回波信号.     

基于三阶累积量及自适应滤波时延估计的管道定位方法

针对直接互相关被动时延估计法定位管道异常振动事件存在噪声干扰影响定位精度的问题,提出了基于三阶累积量及自适应滤波时延估计的管道异常事件定位方法。该方法对顺、反两路异常振动信号进行三阶自累积量和互累积量估计,抑制高斯相关噪声和对称分布噪声。然后利用自适应滤波时延估计算法对三阶自累积量和互累积量信号的时延进行迭代计算,在不依赖先验知识的情况下抑制非高斯相关噪声。经现场实验证明,该方法可以准确地对管道异常事件进行定位,对噪声具有很好的抑制作用,改善了直接互相关时延估计的性能。相对于直接互相关时延估计方法,相对定位误差由2.7%降低到0.6%,定位一致性提高了三倍,平均定位精度可达14m。     

双光束镀膜系统中的信号优化处理研究

为提高光电极值法膜厚监控质量,对微弱光电探测信号设计一套优化的电路处理和数字处理系统。基于双光束镀膜监控思想,提出三级模拟放大电路、双锁相对称放大电路、综合抗干扰技术、数字除法、防脉冲干扰数字滤波、数码显示线性化、剔除奇异数据和ΔR值极值判断等信号综合处理方案。实验表明:电路的测试路输出和参考路输出信噪比均大于500,漂移率≤7%/h;数码显示对反射率响应的灵敏度在整个反射率范围内均比较大,数码显示值的线性回归系数为0.979,低反射率膜的反射率显示分辨极限为0.02%;镀膜中极值点监控信号的不确定度至少比通用系统降低1个数量级,漂移率接近于0。采用此方案对微弱膜厚信号的高精度、高稳定性检测大大提高了膜厚监控系统的静态、动态稳定性和膜厚控制精度,膜厚控制的标准偏差为0.55%。     

消除涌浪对海底声学地层剖面影响的处理技术研究

提出了一种新的消除海底声学地层剖面记录中海洋涌浪影响的办法。该方法在能量比法拾取初值的方法上加以改进,自动拾取剖面记录中受涌浪影响的海底反射面,对拾取的海底反射面进行中值滤波和均值滤波,得到较为光滑的海底面,滤波前后的海底面反射时间差值为涌浪造成的时移量,从原始数据中除去这一时移量,即可消除涌浪对剖面记录的影响。处理后的浅地层剖面分辨率得到很大提高。     

哈依煤气长输管线GIS数据处理技术研究

文章根据长输管线GIS数据结构特点,提出了管线空间定位的方法,并在此基础上提出一种空间距离量算的算法。最后又提出了一种矢量数据(面域)转换为栅格数据的程序算法。     

基于压电传感器的管道泄漏信号可靠性识别技术研究

管道泄漏检测的可靠性主要取决于泄漏信号的信噪比,泄漏信号信噪比的提高主要由传感器和对信号的处理方法决定。在定量分析的基础上,得出了基于压电传感器的管道泄漏检测方法具有比基于压力传感器的负压波法更高的泄漏信号信噪比。通过信号分析,论证了平滑滤波对于提高泄漏信号信噪比的必要性,提出了用区间信号能量来突出泄漏信号的方法。分析比较了实际检测信号幅值、区间信号能量和区间信号平均能量的平方3种方法下泄漏信号的信噪比,提出了用基于区间信号平均能量平方的顺序能量比率法进行管道泄漏信号识别的方法。结果表明该方法可以极大地提高泄漏信号信噪比和泄漏检测可靠性。     

电Fenton法处理阿莫西林废水的试验研究

抗生素生产废水普遍特点是水量水质变化大、成分复杂、有机污染物质含量高、存在生物毒性物质、pH波动大、难以生物降解,且对废水中微生物的生长及新陈代谢过程有抑制作用。其中阿莫西林结构更复杂,与其他类抗生素相比,其性质更稳定。     

Direct-write patterning of indium-tin-oxide film by high pulse repetition frequency femtosecond laser ablation

Ablation of indium oxide doped with tin oxide (ITO) from glass substrates is described. Laser pulse energy and focus spot size were varied in single-pulse, single-spot ablation tests and for ablation of linear features with scanned multiple pulses. The single-pulse ablation threshold of ITO was smaller than that of the glass substrate so the entire thickness of ITO could be removed in a single pulse or with overlying multiple pulses without the possibility of substrate ablation. Linear features could be created at much higher scanning speeds using a high repetition frequency (100 kHz) Yb fiber amplified laser as compared to a lower repetition frequency (2 kHz) laser. An analysis showed that incubation effects lowered ITO ablation thresholds when pulse frequency was high relative to scanning speed, contributing to large feasible scanning speeds for high pulse frequency lasers.     

Optoelectronic measurement of voltage pulse repetition frequency bypicosecond laser diodes

Based on the indirect electro-optic sampling technique, we have designed and tested an optoelectronic frequency meter by using a picosecond gain-switched laser diode. It is the first step towards the construction of a sampler frequency meter for the nondestructive characterization of ultrafast electronic signals     

基于温度和PZT协同控制的激光器频率锁定技术研究

本文针对谐振式光纤陀螺应用需求,提出一种基于激光器温度和PZT协同控制的频率跟踪锁定控制方案,综合利用激光器温度调谐所具有的大范围、PZT电压调谐的高精度高动态技术优势,实现光纤激光器中心频率对谐振腔谐振频率的跟踪锁定。进行了透射式谐振信号的数学仿真,对温度和PZT协同控制方案进行了硬件设计和算法仿真,重点分析了频率跟踪锁定方案中控制参数对锁定稳定性的影响情况。完成了激光器频率锁定系统的研制,实现了激光器中心频率对谐振腔谐振频率的高精度、长时间跟踪锁定,常温条件下1 h频率跟踪锁定精度为4.8×10-9,变温条件下5.5 h频率跟踪锁定精度低至9.74×10-8。上述研究工作为谐振式光纤陀螺长期性能提升奠定了重要的技术基础。     

高频水声换能器匹配层技术研究

在复杂的海洋环境中,为提高对目标的探测效果以获得更多的信息,高频声呐常需要更宽的工作频带.首先,通过声透射原理对不同匹配层材料进行选取与设计;其次,通过有限元仿真对不同匹配层换能器的透射系数、电导谱和发送电压响应展开了分析计算;最后,在理论分析、解析计算和有限元仿真计算的基础上成功研制了单层、双层和三层匹配层高频宽带水...     

高频长缆水声换能器的匹配技术研究

高频换能器接长电缆后谐振频率会发生偏移,导致与工作频率相差甚远,工作点的导纳值与不接长电缆时偏差较大。这使得换能器与发射机和接收机之间的阻抗严重失配。文章对高频长缆水声换能器匹配技术进行研究,通过建立换能器等效电路模型,利用传输线理论,进行四端口匹配网络的设计和仿真,并制作一块匹配电路板。实验结果表明,系统匹配性测试与仿真计算相吻合,提高了系统机电转换效率,证明了该匹配方法的可行性和工程实用性。     

Effect of laser repetition frequency on the structural and optical properties of ZnO thin films by PLD

ZnO thin films were grown on Si (1 1 1) substrates by pulsed laser deposition (PLD) at various laser repetition frequency in order to investigate the structural and optical properties of the films. The optical properties of the films were studied by photoluminescence spectra using a 325 nm He-Cd laser. The structural properties of the films were investigated by XRD measurement. The results suggest that films grown at 5 Hz have excellent UV emission and high-quality crystallinity. Laser repetition frequency can affect the structural and optical properties obviously. In addition, the thickness of all samples is about 200 nm and is not as expected that the film thickness was in direct proportion to laser repetition frequency. The authors think that one laser pulse is not corresponding to one growth instantaneousness. There is a growth ambience containing essential components and partial pressure in the work cavity.     

X-band linac technology for a high repetition rate light source

Traditionally, the pulse-to-pulse charging and switching time for a thyratron-switched line-type modulator has limited the repetition rate of normal-conducting high-energy linacs; however the recent development of solid-state modulators employing IGBT switches has allowed the repetition rate of a high-power modulator to be increased by an order of magnitude. When combined with the high accelerating gradients that can be achieved in an X-band accelerating structure, this enables a relatively compact linear accelerator to be constructed that can operate with a pulse repetition rate in excess of 1 kHz. A study has been undertaken on the issues arising from the operation of an X-band linac in this mode, including a survey of availability and limitations of modulators, klystrons and structures. Close attention has been paid to the dissipation of power in critical parts of the high-power RF chain, both on average and transiently during the high-power RF pulse.     

高频(5G)信号对新能源汽车控制器的辐射研究

随着5G等高频信号快速推广和应用,信号上升边沿极速变陡,对汽车控制器的信号完整性造成极大的威胁.针对5G等高频信号对汽车控制器传输线辐射问题,该文对传输线算法模型进行分析,提出一种边界有限元算法模型,该模型能够对汽车控制器的传输线进行边界界定以此进行理论算法曲线分析;针对汽车控制器传输线互连结构造成的辐射问题,提出一种...     

Direct precipitation of silver nanoparticles induced by a high repetition femtosecond laser

Silver nanoparticles were precipitated directly in Ag⁺ doped silicate glass by a 150 fs, 800 nm, 250 kHz femtosecond laser irradiation. The irradiated pattern turned to yellow without heat treatment. The absorption peak about 400 nm, ascribed to the surface plasmon resonance of the formed silver nanoparticles, was observed. We believe that the reduced Ag atoms, via capturing free electrons created by multi-photon process, may aggregate into the Ag nanoparticles due to femtosecond laser inducing heat accumulation effect. This result has promising applications for the fabrication of 3D multi-colored images inside a transparent material.     

高精密延时电路在高频信号采集方面的研究

本文研究的为高频信号采集系统中的高精密延时电路,主要采用可控恒流源的方式来实现精密定时,最后实现了1ps的最小步进精度和恒流源的可控性,提高了高频信号采集的精度与速度。