排序方式: 共有65条查询结果,搜索用时 15 毫秒
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干涉仪环境振动的外差检测与自适应控制 总被引:8,自引:6,他引:2
测试环境的微振动干扰会引起干涉图的抖动,影响移相干涉仪的测量准确.设计了一种内嵌于移相干涉仪的外差测振光路,对干涉仪所受环境微振动进行实时检测;采用单片RF/IF集成芯片对两路40 MHz的模拟外差信号直接进行比相,简化了通常使用的数字测相方法.在测得环境振动信息后,运用DSP技术和自适应信号处理的方法,实现了基于PZT移相器的自适应振动控制,实验结果表明干涉仪对幅频积不大于100 waves·Hz的环境振动的抑制能力达-39 dB. 相似文献
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An avalanche photodiodes (APDs)-based heterodyne technique for FM/cw laser rangefinder (FM/cw LRF) is described. Based on a modified APDs model, the properties of heterodyne are theoretically analyzed and experimentally demonstrated under different illumination intensities and multiplications, both the amplitude and the signal to noise ratio (SNR) of the difference frequency signal are inversely proportional to the unmultiplied current at a high multiplication and are proportional to the square of multiplication at a low multiplication. 相似文献
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Shearing speckle pattern interferometry is a full-field speckle interferometric technique used to determine surface displacement derivatives. In this paper, a new measurement system of real-time heterodyne shearography interferometry is presented. This system combined with heterodyne measurement, shearography interferometry and time domain signal processing technology can dynamically detect the out-of-plane displacement gradient. The principles and system arrangement are described. Using the Jones matrix, the mathematical expression of light intensity distribution passing through this system is deduced. A preliminary experiment was performed to demonstrate the performance of this new device, and simulations were conducted using the finite element method. Comparison of results shows that quantitative measurement of the displacement derivative has been achieved. 相似文献
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分析了单声光移频器构成的外差式激光多普勒测振计中声光移频器驱动信号的频率稳定性和信号功率对待测振动信号的影响.为了降低声光移频器驱动信号频率漂移的影响,提出双声光移频器构成的外差式激光多普勒测振计,并基于直接数字频率合成技术,以相位噪音低、初始相位可控的芯片AD9912为核心器件,完成了声光移频器驱动信号生成及处理模块的设计.开展了双声光移频器组成的外差式激光多普勒测振计的振动测量实验,结果表明,驱动信号生成装置可以驱动声光移频器正常工作,且测振计的本底噪音在0~10kHz频带范围内呈现平坦分布,0~1kHz频段内噪音得到明显抑制,较单声光移频器构成的外差式激光多普勒测振计有显著改善. 相似文献
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Günther Wernicke Larbi Bouamama Oliver Kruschke Nazif Demoli Hartmut Gruber Sven Krüger 《Optics and Lasers in Engineering》2001,36(5)
Holographic microscopy with conjugate reconstruction for the interferometric determination of three-dimensional displacement was used for the investigation of the mechanical behaviour of micromechanic and microelectronic components. An experimental set-up for the exposure of the holographic interferograms is described for the application of the spatial heterodyne technique, for the application of phase shifting, and for electro-optic holography. Three holograms for different illumination directions recorded on one holographic plate were reconstructed conjugately, and spatial-heterodyne technique as well as phase-shift technique were used to evaluate the interferograms. Only by conjugated reconstruction, it is possible to obtain a perfectly optimised interferometer for the static evaluation method. The evaluation of interferograms, which are strongly disturbed by speckle noise, can be performed successfully. A comparison of the results of the application of these techniques is given. The influence of the speckle effect on the resolution was investigated. 相似文献
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This work proposes a simple measurement technique based on the optical activity of cholesteric liquid crystal (CLC) and circular common-path heterodyne interferometry for measuring small wavelength differences. A circularly polarized heterodyne light passes through a CLC cell and an analyzer, generating an interference signal. When the CLC cell is properly chosen with a circular regime, it has strong optical activity. Accordingly, the phase difference between the left and right circular light of the interference signal depends strongly on the wavelength. As the wavelength changes, variations of the phase difference can be accurately detected by heterodyne interferometry. Substituting the variation of phase difference into specially derived equations, the wavelength variations can be estimated accurately. The feasibility of this method, which is applicable when the wavelength is larger than the product of the pitch and the refractive index of the CLC cell, was demonstrated; it provides the advantages of simple installation, ease of operation, and high accuracy. 相似文献
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在HL-2A装置的电子回旋辐射(ECE)外差测量中,为实现电子温度剖面分布的绝对测量,采用双温度法和磁场扫描法分别对扫频和多道ECE测量系统进行了标定,获得了各道间的相对标定系数,并利用等离子体中心道Thomson散射测量的电子温度对ECE测量系统进行了绝对标定。结果表明,这两种方法都能实现可靠的标定,并对两者的优劣进行了比较和讨论。 相似文献
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The time evolution of a squeezed coherent state conditioned by the results of a single and double heterodyne measurement is discussed. The mean values of quadratures as well as the dynamics of quadrature uncertainties have been obtained within the framework of the theory of continuous measurements based on filtration equations. It has been found that while the mean values depend on the measured noise, the uncertainties in the optical quadratures are deterministic. Explicit solutions for the latter have been provided. Finally, a time development of the squeeze parameter for the posterior squeezed coherent state has been found. 相似文献