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基于低中频采样的超宽带雷达波形产生器误差校正方法
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作者 胡仕兵 陈子为 《成都信息工程大学学报》 2024年第6期689-694,共6页
针对超宽带(UWB)雷达波形合成中正交调制器、混频器、倍频器等模拟环节的误差因素特点,提出一种基于“低中频直接数字产生+倍频”途径的高质量UWB雷达LFM波形数字产生器方案。在频域建立该系统误差的数学模型,提出一种基于频谱对比途径... 针对超宽带(UWB)雷达波形合成中正交调制器、混频器、倍频器等模拟环节的误差因素特点,提出一种基于“低中频直接数字产生+倍频”途径的高质量UWB雷达LFM波形数字产生器方案。在频域建立该系统误差的数学模型,提出一种基于频谱对比途径的系统误差数字预失真校正方法,并进行实验验证和性能分析。该方法将系统失真的校正函数映射到系统数字输入端的波形库中,通过直接对存储的数字波形进行预失真融合处理实现系统误差的校正和补偿。结果表明该方法能够显著地提高产生UWB雷达LFM波形的质量和性能,证实提出的误差校正方法正确、有效和可行。 展开更多
关键词 UWB雷达波形 低中频直接数字产生 倍频器 频域误差模型 频谱对比法 数字预失真
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基于频域模型识别的串补线路方向元件
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作者 张梦瑶 闫海鸥 《河南电力》 2015年第3期20-23,共4页
本文提出了一种基于频域模型识别的串补线路方向元件,解决目前串补方向元件可靠性和灵敏性不足的问题。通过列写基于分布参数的输电线路端口电压方程,构建串补输电线路全频带模型误差函数。利用全频带模型误差和工频量故障定位结果,识... 本文提出了一种基于频域模型识别的串补线路方向元件,解决目前串补方向元件可靠性和灵敏性不足的问题。通过列写基于分布参数的输电线路端口电压方程,构建串补输电线路全频带模型误差函数。利用全频带模型误差和工频量故障定位结果,识别故障点相对于串补电容的位置,区分正反方向故障。该方法仅利用单端量信息,不受串补电容器影响,大大提高了串补输电线路单端量保护的性能,仿真结果验证了该方法的有效性和实用性。 展开更多
关键词 串联补偿电容 频域模型误差 故障定位 方向元件
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Leak detection in pipelines by exclusively frequency domain method 被引量:8
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作者 GUO XinLei YANG KaiLin GUO YongXin 《Science China(Technological Sciences)》 SCIE EI CAS 2012年第3期743-752,共10页
A further development of exclusively inverse frequency domain method for leak detection in pipelines is presented and validated.The location and leakage can be determined by analyzing the difference of transient water... A further development of exclusively inverse frequency domain method for leak detection in pipelines is presented and validated.The location and leakage can be determined by analyzing the difference of transient water head response between the simulated and measured data in frequency domain.The transient signals are generated by portion sharp closure of a valve from the small constant opening and it needs only a few meters of water.The discrete boundary conditions and observation data are both transformed in frequency domain by Laplace transform.Example in numerical simulation is studied for demonstration of this approach.The application of the method to an experimental pipeline confirms the analysis and illustrates successful detection of the single pipeline leak.The precalibration approach is presented to minimize the effect of data and model error and it splits the method into two parts.One uses data from a known state to fit the parameters of the model and the other uses data from the current state for the fitting of leak parameters using the now calibrated model.Some important practical parameters such as wave speed,friction in steady and unsteady state and the adaptability of the method are discussed.It was found that the nonlinearity errors associated with valve boundary condition could be prevented by consideration of the induced flow perturbation curve shape. 展开更多
关键词 pipelines leak detection transient flow FREQUENCY FRICTION ALGORITHM
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