双路AOTF驱动电路及其超声换能器匹配电路的设计

发布时间：2018-06-06 14:27

本文选题：光谱成像 + 双路AOTF　；参考：《中北大学》2017年硕士论文

【摘要】：光谱成像技术是研究目标物质在不同波长下采集的图像信息和光谱信息,并根据其光谱特征对目标物质进行探测和分析,广泛应用于遥感测量、深空探测等领域。随着光谱成像技术的发展,对其光谱测量范围、光谱分辨率、成像清晰度等要求越来越高。当前采用第四代分光技术的声光可调谐滤光器(Acousto-Optic Tunable Filter,AOTF)被广泛应用于光谱成像系统,AOTF作为光谱成像系统的分光器件,其工作波长范围、光谱衍射效率及分辨率等参数对光谱成像系统的性能起到决定性的影响,因此研究如何提高AOTF性能参数对AOTF的发展具有一定的现实意义。AOTF的性能主要受到AOTF驱动电路系统和AOTF内部的超声换能器匹配电路的影响,由此,本文设计了一种高性能AOTF驱动电路以及双路超声换能器匹配电路。AOTF作为功率驱动型器件,按其工作所需功率要求,设计了一种具有一定带宽且功率输出稳定的AOTF驱动电路,其输出功率在50~210MHz带宽范围内稳定在33~35dBm,较好地满足AOTF最佳工作要求。超声换能器作为AOTF重要部件,其在不同频率下具有不同的输入阻抗,当AOTF驱动电路的输出阻抗与换能器输入阻抗失配时会产生能量损耗,导致驱动功率无法最大限度的传递给换能器,从而使AOTF光谱衍射效率降低,影响光谱图像清晰度。为此,通过对超声换能器阻抗频率特性的深入研究,运用滤波器网络匹配理论及射频电路理论,设计了一种频带宽、光谱衍射效率及功率效率高的新型匹配电路。在实验测试平台上,对AOTF驱动电路以及双路超声换能器匹配电路进行实验与优化,最终测得AOTF的光谱衍射效率最高达93.9%,光谱带宽小于5nm,双路换能器匹配电路功率效率达到90%以上,提高了在420~1150nm波段范围内的光谱衍射效率及分辨率。最后对光谱成像系统样机进行外景测试,实测目标的成像质量得到明显改善。
[Abstract]:Spectral imaging technology is to study the image information and spectral information collected by the target material at different wavelengths, and to detect and analyze the target material according to its spectral characteristics. It is widely used in remote sensing, deep space exploration and other fields. With the development of spectral imaging technology, the requirements of spectral measurement range, spectral resolution and imaging clarity are becoming higher and higher. At present, Acousto-Optic Tunable filter AOTFs (Acousto-Optic tunable filter AOTFs) are widely used in spectral imaging system (AOTF) as spectroscopic devices. Parameters such as spectral diffraction efficiency and resolution play a decisive role in the performance of the spectral imaging system. Therefore, the study of how to improve AOTF performance parameters has certain practical significance for the development of AOTF. AOTF performance is mainly affected by AOTF driving circuit system and ultrasonic transducer matching circuit within AOTF. In this paper, a high performance AOTF drive circuit and a dual-channel ultrasonic transducer matching circuit. AOTF is designed as a power driving device. According to the power requirements of its work, an AOTF driving circuit with a certain bandwidth and stable power output is designed. The output power is stable in the bandwidth range of 50 ~ 210MHz and is 33 ~ 35dBm, which can meet the best requirements of AOTF. As an important part of AOTF, ultrasonic transducer has different input impedance at different frequencies. When the output impedance of AOTF drive circuit mismatches with input impedance of transducer, energy loss will occur. Because the driving power can not be transferred to the transducer to the maximum extent, the AOTF spectral diffraction efficiency is reduced and the clarity of the spectral image is affected. Therefore, a novel matching circuit with high frequency bandwidth, spectral diffraction efficiency and power efficiency is designed by studying the impedance frequency characteristics of ultrasonic transducers, using filter network matching theory and radio frequency circuit theory. On the experimental test platform, the AOTF driving circuit and the dual-channel ultrasonic transducer matching circuit are tested and optimized. The spectral diffraction efficiency is up to 93.9, the spectral bandwidth is less than 5 nm, and the power efficiency of the dual-channel transducer matching circuit is over 90%, which improves the spectral diffraction efficiency and resolution in the 420~1150nm band. Finally, the imaging quality of the measured target is improved obviously by the field test of the prototype of the spectral imaging system.
【学位授予单位】：中北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP391.41;TB552

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