共查询到20条相似文献,搜索用时 156 毫秒
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我校“电机节能技术”实验课程中,设置了电动机静态和动态无功补偿研究的内容.为了满足该实验内容的要求,本文对电动机静态和动态无功补偿实验方法进行了研究,设计了电动机无功补偿实验内容和实验装置.本装置能够实现电动机无功功率的静态阶梯补偿和动态跟踪补偿,为学生理解和掌握电动机无功补偿节能方法创造了良好的条件. 相似文献
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Highly accurate group delay measurements in long single-mode fibers were achieved over the full 1200-1600 nm spectral range by measuring phase shifts of a modulated lightwave. The high modulation frequency is shifted down to the kilohertz range using a second optical modulation at the fiber output end, so that low-frequency, ultrasensitive detection and phase measurement can be performed with high-frequency resolution conserved. This results in extremely reliable measurements with a <1-ps resolution using a fully remote light source such as an LED or even a halogen lamp 相似文献
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构建了140 GHz频段的单基雷达用于缩比模型的高分辨力成像和雷达散射截面积(RCS)测量。雷达的相干收发机用全固态的方式实现,其发射信道采用一个Ka波段频率源驱动的倍频链作为本振,在5 GHz的带宽内实现了0.5 mW的输出功率,接收机采用基于肖特基二极管的次谐波混频器实现相干接收。该雷达RCS测试系统显示出高信噪比的特点,获得了大于100 dB的动态范围和3 cm的成像分辨力。除了可实现对目标的逆合成孔径成像,该系统还可完成对旋转目标全方位角的RCS测量。利用该系统对某航空母舰1/720th模型进行了成像实验和RCS测量,模拟了全尺寸目标在P波段的结果。所获得的数据根据缩比定律可为P-波段雷达设计提供参考。 相似文献
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动静态监测光纤光栅传感信号的实验研究 总被引:7,自引:6,他引:1
基于可调谐光纤TF Fabry-Pent(FP)滤波扫描传感光纤Bragg光栅(FBG)反射峰的原理.提出一种新颖的探测方法,分别从动静态两方面监测传感FBG反射谱与TF F-P透射谱的合成谱。实验中.通过加载到TF F-P滤波器的驱动信号的不同,在静态监测下,模拟并分析了光信号功率与转化电压的趋势图以及多次实验中探测到最大信号时两者的关系;用双踪示波器动态实时监测并分析了经光电探测(PD)及其放大调理电路转换后的电压变化信号。实验结果表明.PD探测的最大值与传感FBG反射峰对应。经过标定后的系统分辨率可达1pm,测量精度为0.01nm。 相似文献
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Taylor H. A. Brinton H. C. Wagner T. C. G. Blackwell B. H. Cordier G. R. 《Geoscience and Remote Sensing, IEEE Transactions on》1980,(1):44-49
Identical Bennett radio frequency ion mass spectrometer instruments on the Pioneer Venus Bus and Orbiter have provided the first in-situ measurements of the detailed composition of the planet's ionosphere. The sensitivity, resolution, and dynamic range are sufficient to provide measurements of the solar-wind-induced bow-shock, the ionopause, and highly structured distributions of up to 16 thermal ion species within the ionosphere. The use of adaptive scan and detection circuits and servo-controlled logic for ion mass and energy analysis permits detection of ion concentrations as low as 5 ions/cm3 and ion flow velocities as large as 9 km/s for O+. A variety of commandable modes provides ion sampling rates ranging from 0.1 to 1.6 s between measurements of a single constituent. A lightweight sensor and electronics housing are features of a compact instrument package. 相似文献
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《Microwave Theory and Techniques》1985,33(9):779-783
A method for the measurement of dielectric losses at microwave frequencies for small samples inserted in a resonating cavity is discussed. The method allows static and dynamic determinations of epsilon" by power reflection coefficient measurements in resonance condition and is suitable for experimental setup that use either active or passive frequency techniques. An X-band microwave apparatus based on the passive frequency technique and built up with a right cylindrical cavity resonating in the TE/sub 011/ mode is presented. By means of this apparatus, simultaneous measurements of epsilon' and epsilon" can be performed. Since each determination of the complex permittivity requires times of the order of 1 ms, and the setting is carried out at the beginning of the experiment only, the apparatus is very suitable for dynamic process measurements. The error sources, the overall accuracy, and resolution are discussed and compared with performance achievable with the basic cavity perturbation method. The efficacy of the proposed method is demonstrated by measurements performed on polar liquid mixtures in perturbed cavity conditions. 相似文献
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Fourier变换轮廓术中对测量系统的基本要求 总被引:19,自引:6,他引:19
本文讨论正在正交光轴测量系统中避免阴影和频谱混叠并保证测量精度的方法,采用减小成像光轴和投影光轴之间的夹角的方法避免阴影;增加投影到被测物体上的条纹数,同时提高CCD的分辨率以保证条纹的富里叶谱的基频从其他的频率分量中分离出来,从而提高FTP的测量精度。计算机模拟实验证实了该方法的有效性。 相似文献
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太阳光背景辐射严重影响拉曼激光雷达白天探测的性能。为提高拉曼激光雷达白天探测的高度和精度,设计了激光波长为354.8 nm的拉曼激光雷达系统,讨论了354.8 nm和532 nm激光光源对拉曼激光雷达探测性能的影响,完成了系统的光路设计。偏振分光棱镜和1/4波片组成的光开关与收发合置的望远镜相结合,减小了系统的接收视场角,优化了白天探测的性能。以最小的温度不确定度为标准,通过仿真分析选取了转动拉曼通道干涉滤光片的各项参数,并对系统的探测性能进行了仿真。仿真过程中激光能量取200 mJ,频率50 Hz,积分时间20 min,距离分辨率105 m。收发合置的拉曼激光雷达系统在考虑退偏的情况下,白天探测的温度不确定度在3180 m以下小于1 K。白天探测水汽混合比的统计误差在2400 m以下,小于0.001 g/kg。仿真结果表明,白天探测的性能得到了一定程度的提高。 相似文献
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This paper describes the design and verification of an ultra-wideband 6–14 GHz frequency modulated continuous wave (FMCW) primary radar system with very high range resolution. The design and measurement results of the utilized signal generator and receiver are presented. The signal generator features a 86% relative continuous tuning range and average phase noise of −106 dBc/Hz at 1 MHz offset to the carrier. The radar system utilizes a hybrid structure where the voltage controlled oscillator was fabricated using 130 nm SiGe BiCMOS technology and the lower frequency components are off-the-shelf. Free field measurements of the radar showcase an unprecedented combination of 3 cm range resolution, low phase noise and low operating frequency of 6–14 GHz for inherently higher range. 相似文献