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高精度TDOA时差测试技术研究 被引量:1
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作者 李伟 《中国无线电》 2016年第1期58-61,共4页
通过对基于相关类算法的TDOA系统时差测试技术理论推导,指出该技术成立的前提条件为针对平稳信号,对于非平稳信号将会引入系统误差;数学模型计算表明,在低通带限平坦谱条件下,相关类算法对于多径信号有效分离的最小时间差为1/B(B为信号... 通过对基于相关类算法的TDOA系统时差测试技术理论推导,指出该技术成立的前提条件为针对平稳信号,对于非平稳信号将会引入系统误差;数学模型计算表明,在低通带限平坦谱条件下,相关类算法对于多径信号有效分离的最小时间差为1/B(B为信号带宽)。当多径信号时间差小于该值时,相关类算法无法有效分辨出多径信号,从而引入系统误差。针对以上不足,本文给出一种精确测量信号到达时间差的设计方案。该方案致力于对两路信号首次到达的时间差进行检测,通过对信号检波、整形之后利用门电路的组合实现时间差的绝对值计算,同时利用D触发器判断最先到达的信号,从而完成信号到达时间差的准确计算。该方案能够实现对任意两路信号的时差计算,并完全不受多径影响,且成本低廉,对新型高精度TDOA系统的设计具有现实意义。 展开更多
关键词 TDOA 时差测试 自相关 时差分辨率
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Lightning Induced Surge on the Distribution Lines in the House near by the Lightning Point
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作者 Aiko Takahara Ryoji Oshiro Eiji Kaneko 《Journal of Energy and Power Engineering》 2012年第5期840-844,共5页
Recently, a lightning surge is recognized as one of the biggest risks to the society. If the surges induced by lightning invade into low voltage distribution lines, there might be a possibility of giving some severe d... Recently, a lightning surge is recognized as one of the biggest risks to the society. If the surges induced by lightning invade into low voltage distribution lines, there might be a possibility of giving some severe damages to the systems. Therefore, it is necessary to examine these induced phenomena. FDTD (finite difference time domain) method which treats objects as three-dimensional solid circuits is applied to analyze these induced phenomena. VSTL (Virtual Surge Test Lab.) is the surge analysis simulation program using FDTD method. In this paper, the lightning induced phenomena on the low voltage distribution line in the house are analyzed by using VSTL. In this paper, investigation results about induced surge when a lightning struck the point nearby the house, and about a suppressing effect of surges by comparing the results of analysis with and without SPD (surge protective device) are shown. As a result, it is confirmed that SPD is effective for suppressing lightning surge. 展开更多
关键词 Lightning surge induced phenomena FDTD method distribution line VSTL.
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