共查询到19条相似文献,搜索用时 62 毫秒
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一种多接收通道的增益与相移失配均衡方法 总被引:1,自引:0,他引:1
针对多个接收通道增益、相移特性的不一致给测向带来很大误差,提出一种通过标准测试信号,建立通道频率传输特性补偿数据库的方法,对实际接收信号进行精确的通道均衡补偿,有效解决了接收通道增益失配与相移失配问题及减少了测向误差.仿真证明:在比幅法测向系统中.间距d越小,幅度补偿带来的好处越明显;在比相幅法测向系统中,间距d在较大的变化范围内.相位补偿对测向误差都有明显改善.这种算法具有简洁、运算速度快的特点,适合天线数目、信道数目不多的中、小型可移动测向设备. 相似文献
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在综合考虑偏度误差与随机误差的基础上,分析了传声器通道失配误差和位置失配误差对平面近场声全息(NAH)分析的影响,从实空间和波数域两方面对全息面和重建面上引起的统计误差进行了详细的理论推导,并以理想点源作为研究对象对理论结果进行了验证。理论推导与数值仿真均表明:在偏度误差和随机误差取值相当的条件下,在波数域内,它们在全息面及重建面上产生的统计误差的偏差都较小,且偏度误差引起的归一化偏差要大于随机误差引起的归一化偏差,但两者在全息面及重建面上产生的统计误差的方差大相径庭,偏度误差引起的归一化方差很小可以完全忽略不计,而随机误差引起的归一化方差在辐射圆外呈指数倍数放大,会对NAH的重建结果将会产生严重的影响,综合考虑后,随机误差比偏度误差对NAH重建精度的影响更大。 相似文献
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基于均衡充电技术的智能应急灯电池管理系统设计与实现 总被引:1,自引:0,他引:1
设计了一种基于分时复用和电池均衡技术的多工作模式智能LED应急灯电池管理系统,它具有电池监测和均衡、电池充放电保护、多工作模式切换、遥控等功能,满足企业对应急灯的需求,延长了电池使用寿命,进一步提高了应急灯的安全性和可靠性。 相似文献
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本文通过讲述HFC网回传通道汇聚噪声和汇聚均衡的产生,及对HFC网双向传输造成的危害,谈怎样解决好回传通道上所产生的汇聚噪声和汇聚均衡的两大难题,确保双向HFC网高质量地运行。 相似文献
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为实现机载合成孔径雷达(Synthetic Aperture Radar,简称SAR)实际回波数据中的运动目标聚焦成像,本文在用前置滤波法检测出运动目标的基础上,提出了利用目标子图像匹配方法来估计动目标的方位向速度,得到相应的运动目标聚焦参考函数,然后对运动目标进行聚焦成像,并给出了利用该方法得到的运动目标聚焦图像.成像结果表明,目标子图像匹配方法对动目标成像是有效的,易于工程实现,有实际应用价值. 相似文献
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为有效评估地面目标的伪装性能,提出了一种采用地基合成孔径雷达(Ground Based-Synthetic ApertureRadar,GB-SAR)模拟观测获取目标SAR信息的试验和伪装性能评估方法。该方法在分析伪装目标的SAR成像特性的基础上,采用地基机动平台上的SAR系统对地面伪装目标进行模拟卫星SAR观测几何的数据获取,在此基础上通过目标散射特性分析等实现伪装性能评估。首先分析了地基SAR系统模拟星载SAR侦察的必要性;其次,介绍了适用于模拟星载SAR观测的典型地基SAR系统组成。针对伪装性能评估,介绍了如何从目标特性的角度分析伪装效果的方法;并指出了该方法适用于多种雷达伪装设备的评估。 相似文献
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The traditional Range Doppler (RD) algorithm is unable to meet practical
needs owing to the limit of resolution. The order of fractional Fourier Transform (FrFT)
and the length of sampling signals affect SAR imaging performance when FrFT is
applied to RD algorithm. To overcome the above shortcomings, the purpose of this paper
is to propose a high-resolution SAR image algorithm by using the optimal order of FrFT
and the sample length constraints for the range direction. The expression of the optimal
order of SAR range signals via FrFT is deduced in detail. The initial sample length and
its constraints are proposed to obtain the best sample length of SAR range signals.
Experimental results demonstrate that, when the range sampling-length changes in a
certain interval, the best sampling-length will be obtained, which the best values of the
range resolution, PSLR and ISLR, will be derived respectively. Compared with
traditional RD algorithm, the main-lobe width of the peak-point target of the proposed
algorithm is narrow in the range direction. While the peak amplitude of the first side-lobe
is reduced significantly, those of other side-lobes also drop in various degrees. 相似文献
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M. Pieraccini L. Noferini D. Mecatti G. Luzi C. Atzeni R. Persico 《Research in Nondestructive Evaluation》2013,24(2):71-83
This article deals with different processing techniques applied to data gathered by a novel step-frequency penetrating radar in a measurement survey of the walls of the historical room “Salone dei 500” in Palazzo Vecchio (Firenze, Italy). The aim of the investigation was to detect discontinuities in the masonry walls, possibly corresponding to a cavity containing fragments of the lost fresco of the Battle of Anghiari by Leonardo da Vinci. Data have been processed by means of two different techniques. The first one is a time domain analysis compensating for dielectric losses inside the medium, and the second one is based on a one-dimensional inverse scattering approach. Even if based on different principles, both techniques reveal the presence of a discontinuity in the eastern wall of the room at a depth between 10 and 20 cm, whereas no discontinuity traces are observed in the other walls. 相似文献