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DDFS spurious signals due to amplitude quantization in absence of phase-accumulator truncation
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作者 Tian Xinguang Liu Xin +1 位作者 Chen Hong Duan Miyi 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2009年第3期485-492,共8页
Spurious signals in direct digital frequency synthesizers (DDFSs) are partly caused by amplitude quantization and phase truncation, which affect their application to many wireless telecommunication systems. These si... Spurious signals in direct digital frequency synthesizers (DDFSs) are partly caused by amplitude quantization and phase truncation, which affect their application to many wireless telecommunication systems. These signals are deterministic and periodic in the time domain, so they appear as line spectra in the frequency domain. Two types of spurious signals due to amplitude quantization are exactly formulated and compared in the time and frequency domains respectively. Then the frequency spectra and power levels of the spurious signals due to amplitude quantization in the absence of phase-accumulator truncation are emphatically analyzed, and the effects of the DDFS parameter variations on the spurious signals are thoroughly studied by computer simulation. And several important conclusions are derived which can provide theoretical support for parameter choice and spurious performance evaluation in the application of DDFSs. 展开更多
关键词 spurious signal direct digital frequency synthesizer amplitude quantization phase truncation power level.
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Amplitude variation characteristics of active source airgun signals at Qilian Mountain
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作者 Xuzhou Liu Yuansheng Zhang +3 位作者 Zhiguo Liu Manzhong Qin Rui Zou Xiao Guo 《Earthquake Science》 2021年第2期161-167,共7页
In this study,Qilian Mountain active source airgun signals recorded at 79 stations were obtained after stacking waveforms from July 2015 to December 2016.Based on analysis of the amplitude variation characteristics of... In this study,Qilian Mountain active source airgun signals recorded at 79 stations were obtained after stacking waveforms from July 2015 to December 2016.Based on analysis of the amplitude variation characteristics of the airgun signals,the following conclusions were drawn:along the NW-SE fault distribution direction of the Qilian Mountain area,the decrease in amplitude of airgun signals was relatively slow in relation to the epicentral distance,while the decrease in amplitude in the direction perpendicular to the fault was relatively fast.This difference may be related to the energy loss of seismic waves reflecting and scattering by the regional faults mainly distributed along the NW-SE direction,which are caused by tectonic compression of the QinghaiTibet and Alxa blocks. 展开更多
关键词 airgun signal amplitude variation seismic wave directional difference Qilian Mountain.
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Transfer characteristics of dynamic biochemical signals in non-reversing pulsatile flows in a shallow Y-shaped microfluidic channel: signal filtering and nonlinear amplitude-frequency modulation
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作者 Zongzheng CHEN Weimo YUAN +4 位作者 A.R.AZIZ Zhengming GAO Depei ZENG Bo LIU Kairong QIN 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2017年第10期1481-1496,共16页
The transports of the dynamic biochemical signals in the non-reversing pulsatile flows in the mixing microchannel of a Y-shaped microfluidic device are ana- lyzed. The results show that the mixing micro-channel acts a... The transports of the dynamic biochemical signals in the non-reversing pulsatile flows in the mixing microchannel of a Y-shaped microfluidic device are ana- lyzed. The results show that the mixing micro-channel acts as a low-pass filter, and the biochemical signals are nonlinearly modulated by the pulsatile flows, which depend on the biochemical signal frequency, the flow signal frequency, and the biochemical signal transporting distance. It is concluded that, the transfer characteristics of the dynamic biochemical signals, which are transported in the time-varying flows, should be carefully considered for better loading biochemical signals on the cells cultured on the bottom of the microfluidic channel. 展开更多
关键词 shallow Y-shaped microfluidic channel dynamic biochemical signal non-reversing pulsatile flow nonlinear amplitude-frequency modulation Taylor-Aris disper-sion
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Stochastic Resonance in a Single-Mode Laser Driven by Quadratic Colored Pump Noise:Effects of Biased Amplitude Modulation Signal 被引量:8
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作者 ZHANG Liang-Ying CAO Li WU Da-Jin 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第7期143-148,共6页
A single-mode laser noise model driven by quadratic colored pump noise and biased amplitude modulationsignal is proposed.The analytic expression of signal-to-noise ratio is calculated by using a new linearized procedu... A single-mode laser noise model driven by quadratic colored pump noise and biased amplitude modulationsignal is proposed.The analytic expression of signal-to-noise ratio is calculated by using a new linearized procedure.Itis found that there are three different typies of stochastic resonance in the model:the conventional form of stochasticresonance,the stochastic resonance in the broad sense,and the bona fide SR. 展开更多
关键词 stochastic resonance quadratic colored pump noise bias amplitude modulation signal
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The application of Gaussian distribution deconvolution method to separate the overlapping signals in the 2D NMR map
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作者 Kou-Qi Liu Zheng-Chen Zhang Mehdi Ostadhassan 《Petroleum Science》 SCIE EI CAS CSCD 2023年第3期1513-1520,共8页
The 2D NMR(T_(1)-T_(2))mapping technique,which can be used to separate different proton populations from various sources(hydroxyls,solid organic matter,free water,and free HC)has gained attention in petroleum industry... The 2D NMR(T_(1)-T_(2))mapping technique,which can be used to separate different proton populations from various sources(hydroxyls,solid organic matter,free water,and free HC)has gained attention in petroleum industry.To separate proton contributions,a fixed straight line is commonly employed to separate different regions representing proton sources on the map.However,some of these regions(Region 1 and 2)might overlap which makes extracting the NMR signal amplitude from these regions inaccurate.In order to solve this issue,in this study,we applied the Gaussian distribution deconvolution method to separate the T_(1)and T_(2)relaxation distributions and then derived the signal amplitude of each region instead of following the common fixed line approach.Next,we employed this method to analyze several shale samples from the literature and compared the results following both methods to verify our methodology.Finally,samples from the Bakken Shale were studied to separate signals from Region 1 and Region 2 and corelated the results with geochemical properties that were obtained from programmed(Rock Eval)pyrolysis.Results demonstrated an improvement in their relation when our approach is employed compared to the fixed line technique to differentiate signal from overlapping regions.This means the Gaussian distribution deconvolution method can be used with confidence to provide us with more accurate petrophysical and geochemical understanding of complex formations. 展开更多
关键词 2D NMR signal amplitude Gaussian distribution Shale formations
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A new tracking error detection method using amplitude difference detection for signal waveform modulation multi-level discs 被引量:1
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作者 严明铭 裴京 潘龙法 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第10期319-323,共5页
The sub-land/sub-pit affects the characteristic of the tracking error signal which is generated by the conventional differential phase detection (DPD) method in the signal waveform modulation multi-level (SWML) re... The sub-land/sub-pit affects the characteristic of the tracking error signal which is generated by the conventional differential phase detection (DPD) method in the signal waveform modulation multi-level (SWML) read-only disc. To solve this problem, this paper proposes a new tracking error detection method using amplitude difference. Based on the diffraction theory, the amplitude difference is proportional to the tracking error and is feasible to be used for obtaining the off-track information. The experimental system of the amplitude difference detection method is developed. The experimental results show that the tracking error signal derived from the new method has better performance in uniformity and signal-to-noise ratio than that derived from the conventional DPD method in the SWML read-only disc. 展开更多
关键词 signal waveform modulation multi-level technology tracking error amplitude difference
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Stochastic Resonance in Linear Region of a Single-Mode Laser: Effects of Amplitude Modulation of Signal 被引量:1
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作者 ZHANG Liang-Ying CAO Li WU Da-Jin 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第5期1310-1314,共5页
A single-mode laser noise model driven by quadratic colored pump noise and amplitude modulation signal is proposed. The real and imaginary parts of the pump noise are assumed to be cross-correlation. The effect of cro... A single-mode laser noise model driven by quadratic colored pump noise and amplitude modulation signal is proposed. The real and imaginary parts of the pump noise are assumed to be cross-correlation. The effect of cross- correlation of noise and amplitude modulation of signal on laser statistical properties is studied by using the linearized approximation. The analytic expression of signal-to-noise ratio (SNR) is calculated. It is found that the phenomena of stochastic resonance (SR) respectively exist in the curves of the SNR versus the noise cross-correlation coefficient λ and the SNR versus the pump parameter a, as well as the SNR versus the signal frequency ω in our model. It is shown that there are three different typies of SR in the model: the conventional form of SR, the SR in the broad sense, and the bona fide SR. 展开更多
关键词 stochastic resonance single-mode laser amplitude modulation signal
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Research on the Seismic Wave Characteristics of Low Frequency Signals before the Alxa Left Banner MS5.8 Earthquake in Inner Mongolia,China
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作者 Liang Shasha Gao Lixin +2 位作者 Dai Yong Ge Gen Wang Lei 《Earthquake Research in China》 CSCD 2018年第3期367-376,共10页
In order to search for the seismic wave characteristics of low frequency signals in the Alxa Left Banner region,Inner Mongolia,the low frequency signals of seismic wave data are extracted from the earthquakes of MS5. ... In order to search for the seismic wave characteristics of low frequency signals in the Alxa Left Banner region,Inner Mongolia,the low frequency signals of seismic wave data are extracted from the earthquakes of MS5. 8 in 2015 and MS5. 0 in 2016 in this area. The results show that:① Before the MS5. 8 earthquake,the seismic stations located near the epicenter in Wuhai,Dongshengmiao,and Shizuishan recorded seismic waves that showed the phenomenon of spectrum shift from high to low frequency.② The low frequency signals recorded by different stations have obvious difference.③ According to the data recorded by the station closest to the epicenter,low-frequency signals were recorded about120 hours before the earthquake and had obvious anomalies. This may reflect slow slip before the earthquake. 展开更多
关键词 Low frequency signal The FOURIER transform Spectrum SHIFT The maximum ENVELOPE amplitude
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GNSS线极化天线干涉信号反演土壤湿度算法测试
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作者 李杰 杨东凯 +1 位作者 洪学宝 王峰 《北京航空航天大学学报》 EI CAS CSCD 北大核心 2024年第3期874-885,共12页
利用全球导航卫星系统干涉信号(GNSS-IR)测量土壤湿度已成为热门的研究课题。搭载低成本线性极化天线的智能手机可以方便快捷采集干涉信号信噪比(SNR)。分别仿真垂直和水平线性极化天线采集的GNSS干涉信号,给出2种极化方式下干涉信号SN... 利用全球导航卫星系统干涉信号(GNSS-IR)测量土壤湿度已成为热门的研究课题。搭载低成本线性极化天线的智能手机可以方便快捷采集干涉信号信噪比(SNR)。分别仿真垂直和水平线性极化天线采集的GNSS干涉信号,给出2种极化方式下干涉信号SNR波形和反射率随卫星高度角变化的结果。对于垂直极化分量,电磁波会在入射角65°~85°左右时发生全透射,导致干涉信号振荡效果消失,而水平极化不存在该现象。同时,分别仿真右旋圆极化(RHCP)直射和左旋圆极化(LHCP)反射天线采集的GNSS信号,并计算直反射信号的幅值比。在仿真基础上分别利用不同极化天线进行实验,结果表明:采用线性极化天线采集的GNSS干涉信号振荡效果几乎不受卫星高度角的限制,可以为土壤湿度反演提供更多的有效数据,并且反演得到的土壤湿度与同位数据具有良好的一致性,两者的相关性达到0.95。使用搭载圆极化天线的双通道接收机采集北斗系统卫星数据进行对比,相关性达到0.91。对于不同的设备,智能手机采集的GNSS数据占用空间相对比于双通道接收机降低1%,且反演结果相关性接近,由于干涉信号提取直反射信号需要一定的振荡周期,故反演结果的时间分辨率要低于双通道接收机。 展开更多
关键词 全球导航卫星系统干涉信号 线性极化 信号幅值比 土壤湿度 圆极化
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运行状态下GIS设备振动特性差异性研究
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作者 徐惠 刘正阳 +3 位作者 罗传仙 刘诣 张静 李艳鹏 《高压电器》 CAS CSCD 北大核心 2024年第6期43-49,56,共8页
机械类缺陷/故障是当前GIS设备最为常见的问题之一,对于此类缺陷目前尚无可用的现场检测装置及机械缺陷评估方法。文中通过现场检测方式,开展了220 kV及550 kV GIS不同气室的振动特征对比分析研究。研究结果表明:三相母线室的振幅最高,... 机械类缺陷/故障是当前GIS设备最为常见的问题之一,对于此类缺陷目前尚无可用的现场检测装置及机械缺陷评估方法。文中通过现场检测方式,开展了220 kV及550 kV GIS不同气室的振动特征对比分析研究。研究结果表明:三相母线室的振幅最高,可能原因在于三相母线在壳体上产生的磁感应强度更大,壳体的振动幅值更大;同类气室不同测点的幅频特性相关系数均在0.993以上,不同类气室的测量结果相关系数较低,幅频特性及其相关系数可以在一定程度上表征GIS的不同气室振动状态;振幅和相位、检测位置和电压等级之间相关性不强;大多数气室主要频率成分均为100 Hz,避雷器振动的主要频率变为300 Hz,可能与避雷器内部轻微缺陷有关。 展开更多
关键词 GIS 振动信号 现场检测 幅频特性
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基于单PD直接检测Twin-SSB-QPSK信号的光纤通信系统
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作者 张洪波 刘娇 +3 位作者 凌味未 张敏 万峰 蔡炬 《通信学报》 EI CSCD 北大核心 2024年第6期187-195,共9页
针对孪生单边带正交相移键控(Twin-SSB-QPSK)信号在光传输过程中的高成本问题,提出了一种在接收端采用单光电探测器(PD)直接检测Twin-SSB-QPSK信号的光纤通信系统。在接收端不需要采用光带通滤波器(OBPF)对Twin-SSB-QPSK信号的两路光单... 针对孪生单边带正交相移键控(Twin-SSB-QPSK)信号在光传输过程中的高成本问题,提出了一种在接收端采用单光电探测器(PD)直接检测Twin-SSB-QPSK信号的光纤通信系统。在接收端不需要采用光带通滤波器(OBPF)对Twin-SSB-QPSK信号的两路光单边带信号进行分离,而是利用直接检测的拍频效应,通过单PD直接检测孪生的两路光单边带QPSK信号产生相干叠加的单路16阶正交幅度调制(16QAM)信号。仿真演示了两路56 Gbit/s的QPSK信号叠加为一路112 Gbit/s的16QAM信号,并与传统的单路16QAM信号传输方案进行了仿真对比。仿真结果表明,该方案在降低系统器件要求和部署成本的同时并没有带来额外的功率代价。 展开更多
关键词 光纤通信 正交相移键控 正交幅度调制 信号合成 直接检测
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一种压电换能器热释电防护电路设计
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作者 李世国 潘灿 +3 位作者 赵德峰 母江东 李军 何知益 《压电与声光》 CAS 北大核心 2024年第2期253-258,263,共7页
该文探讨了压电材料热释电效应产生的机理,得出压电换能器中压电陶瓷材料受温度变化会产生极化电荷,引起的热释电压会使压电换能器输出信号幅值增大,导致输出失效。因此针对热释电问题提出了两点解决方案。经过对比分析设计了一种ESD保... 该文探讨了压电材料热释电效应产生的机理,得出压电换能器中压电陶瓷材料受温度变化会产生极化电荷,引起的热释电压会使压电换能器输出信号幅值增大,导致输出失效。因此针对热释电问题提出了两点解决方案。经过对比分析设计了一种ESD保护电路来解决热释电问题。该ESD保护电路通过设计一种改进型二极管钳位电路,针对压电换能器存在的极化电荷构建热释电释放环路,消除了热释电压对有用信号收发的影响。最后,通过对比实验验证了设计方案的可行性。 展开更多
关键词 压电换能器 热释电效应 信号幅值增大 ESD保护电路 改进型二极管钳位电路
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AM-FM算子分解方法在滚动轴承故障诊断中的应用
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作者 黄武 郑近德 +2 位作者 童靳于 潘海洋 刘庆运 《机械科学与技术》 CSCD 北大核心 2024年第7期1257-1265,共9页
基于算子的零空间追踪算法能够实现复杂信号的自适应分解,其关键在于信号模型的构造与求解。通过定义一种新的可完全消除调幅调频信号的调幅调频算子(AFO),进一步建立了一种基于AFO的信号分解新模型。为了提高参数对信号分解的鲁棒性,... 基于算子的零空间追踪算法能够实现复杂信号的自适应分解,其关键在于信号模型的构造与求解。通过定义一种新的可完全消除调幅调频信号的调幅调频算子(AFO),进一步建立了一种基于AFO的信号分解新模型。为了提高参数对信号分解的鲁棒性,将非参数正则化(NPR)方法用于解决上述模型的约束优化问题,提出了一种基于NPR的自适应信号分解方法——NPR-AFO。论文将NPR-AFO方法引入到机械故障诊断中,并通过仿真和滚动轴承局部故障实测数据分析,与现有的其他分解方法进行了对比。结果表明:所提方法不仅可以有效的提取故障特征,而且状态故障特征更加明显。 展开更多
关键词 经验模态分解 零空间算子 调幅调频信号 故障诊断 非参数正则化
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基于JADE-斜投影的鲁棒波束形成算法
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作者 程永杰 李纯 +1 位作者 刘帅 金铭 《系统工程与电子技术》 EI CSCD 北大核心 2024年第2期401-406,共6页
针对矩阵重构类波束形成算法对阵列幅相误差敏感的问题,提出一种基于盲源信号分离和斜投影的矩阵重构鲁棒波束形成算法。首先,依靠盲源分离技术得到接收信号和混合矩阵,结合期望信号先验信息完成混合矩阵中信号导向矢量的搜索。然后,利... 针对矩阵重构类波束形成算法对阵列幅相误差敏感的问题,提出一种基于盲源信号分离和斜投影的矩阵重构鲁棒波束形成算法。首先,依靠盲源分离技术得到接收信号和混合矩阵,结合期望信号先验信息完成混合矩阵中信号导向矢量的搜索。然后,利用盲源分离得到的信号协方差矩阵完成阵列幅相误差估计。最后,基于幅相误差校准的混合矩阵和斜投影思想,构建各干扰的斜投影算子,将接收数据分别向干扰斜投影空间进行投影,得到对应的干扰信号,完成干扰噪声协方差矩阵重构。仿真结果表明,所提方法对阵列幅相误差具有较好的鲁棒性,验证了算法的有效性。 展开更多
关键词 鲁棒波束形成 矩阵重构 幅相误差 盲源信号分离 斜投影
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基础实验试题A:线圈耦合效率的研究
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作者 陈羽 唐强 蔡志岗 《物理实验》 2024年第5期22-28,34,共8页
介绍了第9届全国大学生物理实验竞赛基础实验试题A的实验内容,给出了参考解答并分析了学生作答情况.基础实验试题A为电磁学题目,试题包含正弦信号典型参量与功率的测量、未知元件的判别、线圈电流的非接触测量、耦合损耗分析与效率优化... 介绍了第9届全国大学生物理实验竞赛基础实验试题A的实验内容,给出了参考解答并分析了学生作答情况.基础实验试题A为电磁学题目,试题包含正弦信号典型参量与功率的测量、未知元件的判别、线圈电流的非接触测量、耦合损耗分析与效率优化4个部分.试题在大学物理实验中交流信号基本参量测量的基础上,重点考查学生对示波器等常见电学仪器的使用、常见电学元件特性的掌握、正弦信号与简谐运动的分析和对电磁感应物理图像的理解与综合应用能力. 展开更多
关键词 电磁感应 正弦信号 复振幅 耦合效率
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多通道离散量在线监测模块的设计与实现
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作者 陈广 周珂 +1 位作者 李吉超 曹建虎 《仪表技术与传感器》 CSCD 北大核心 2024年第4期38-42,共5页
随着工业领域电子设备集成度的不断提高,针对多类型、大数量离散量信号的实时监测需求,设计了基于FPGA与CPCI总线的多通道离散量在线监测模块。通过扩展多个传感器芯片并内嵌FPGA幅值计算程序,该模块可并行测量96路输入信号幅值。对外采... 随着工业领域电子设备集成度的不断提高,针对多类型、大数量离散量信号的实时监测需求,设计了基于FPGA与CPCI总线的多通道离散量在线监测模块。通过扩展多个传感器芯片并内嵌FPGA幅值计算程序,该模块可并行测量96路输入信号幅值。对外采用CPCI总线通用接口,可在线更新检测参数,支持后走线,理论上可扩展实现任意数量离散量信号的在线监测,克服了传统离散量测试电路体积大、测量参数固定、信号通道少的问题。经过通道一致性、实时性、可靠性测试验证,该模块测量准确,性能稳定,能够满足测试设备小型化、集成化的使用要求。 展开更多
关键词 多通道 离散量 实时 在线监测 幅值
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幅相误差对体积阵MVDR波束形成的影响
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作者 黄燕 焦君圣 +1 位作者 郭世旭 赵鹏 《水下无人系统学报》 2024年第1期139-146,共8页
体积阵是一种由多个水听器组成的立体阵列,能够增大潜标接收基阵的孔径,获得较大的空间增益,工程中多将其制作成具有收合、展开功能的阵列应用于低频吊放声呐。由于各水听器通道内器件参数和幅度增益不一致,体积阵的每个阵元接收到的信... 体积阵是一种由多个水听器组成的立体阵列,能够增大潜标接收基阵的孔径,获得较大的空间增益,工程中多将其制作成具有收合、展开功能的阵列应用于低频吊放声呐。由于各水听器通道内器件参数和幅度增益不一致,体积阵的每个阵元接收到的信号之间存在幅相误差。文中通过建立存在幅相误差时的双圆环体积阵模型,从统计学角度分析了幅相误差对其协方差矩阵、最小方差无畸变(MVDR)波束形成器的输出信噪比(SNR)、阵增益以及方位估计精度的影响。计算机仿真结果表明,阵列幅相误差的存在会导致MVDR波束形成器的输出SNR和阵增益降低;对于相位误差而言,当输入SNR在-5 dB以上时,这种影响随输入SNR的增大越来越明显;对于幅度误差而言,当输入SNR在-10 dB以上时,幅度误差对MVDR波束形成器的输出SNR和阵增益的影响会更显著;并且,相比于幅度误差,MVDR波束形成的方位估计精度对相位误差更加敏感。 展开更多
关键词 水听器 体积阵 幅相误差 输出信噪比 阵增益 方位估计精度
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基于轻量化RF算法的高阶QAM信号OSNR估计方法
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作者 张明烨 欧洺余 +1 位作者 倪钱 朱宏娜 《光通信技术》 北大核心 2024年第3期64-67,共4页
针对光信噪比(OSNR)估计复杂度高、计算量大的问题,提出了一种基于轻量化随机森林(RF)算法的高阶正交幅度调制(QAM)信号OSNR估计方法。该方法通过将不同OSNR的高阶QAM信号映射为不同的星座图数据集,并利用这些数据集来训练RF模型,从而实... 针对光信噪比(OSNR)估计复杂度高、计算量大的问题,提出了一种基于轻量化随机森林(RF)算法的高阶正交幅度调制(QAM)信号OSNR估计方法。该方法通过将不同OSNR的高阶QAM信号映射为不同的星座图数据集,并利用这些数据集来训练RF模型,从而实现OSNR的快速估计。仿真结果表明:采用基于轻量化RF算法估计64QAM和128QAM信号的OSNR,在系统OSNR真实值为5~30 d B时,2种调制格式的OSNR估计准确率均接近100%;64QAM信号OSNR估计值的平均绝对误差(MAE)为0.08 d B,128QAM的MAE为0.12 d B,比基于长短期记忆(LSTM)算法的信号OSNR估计结果更准确。 展开更多
关键词 光纤通信 随机森林 光信噪比 高阶正交幅度调制
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基于Radon变换的宽带信号多域参数同时测量方法
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作者 于涵 唐莽 +2 位作者 刘建 曹霄 鲍成浩 《航天电子对抗》 2024年第3期54-58,共5页
实际电子监测设备的作战环境复杂多变,辐射源个数、工作频率、工作带宽、到达角度等多域参数信息对于实现工作场景的实时精确感知至关重要。提出一种基于Radon变换的宽带信号多域参数同时测量方法,实现多个宽带信号多域重点工作参数的... 实际电子监测设备的作战环境复杂多变,辐射源个数、工作频率、工作带宽、到达角度等多域参数信息对于实现工作场景的实时精确感知至关重要。提出一种基于Radon变换的宽带信号多域参数同时测量方法,实现多个宽带信号多域重点工作参数的同时快速测量,大大提升低信噪比条件下监测目标特性的多维实时感知能力。该方法结合数字信道化结构及二重FFT算法实现全侦收频段及全侦收角度的空时域联合功率聚焦,并生成作战场景的空时二维频谱幅度图,利用Radon变换算法实现不同映射角度的线性积分运算,构建合适的检测门限,推导计算全场景多目标多参数测量结果。实验显示,该方法可以有效提升弱信号的参数测量精度,实现多目标多域参数同时测量。 展开更多
关键词 宽带信号 多域参数 二维频谱幅度图 RADON变换 同时测量 低信噪比
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基于声信号的航空发动机风扇叶盘共振特征识别
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作者 何刘海 齐成婧 +3 位作者 侯明 吴桂娇 刘飞春 徐福健 《推进技术》 EI CAS CSCD 北大核心 2024年第7期250-259,共10页
航空发动机风扇叶盘模态密集,激励源丰富,使得风扇叶片容易共振出现裂纹、掉块等故障。针对振动应力、叶尖振幅和传声器阵列等测试方法复杂、成本高、周期长等特点,在风扇进气管道口布置单个传声器测量进口声信号,并对声信号进行时频分... 航空发动机风扇叶盘模态密集,激励源丰富,使得风扇叶片容易共振出现裂纹、掉块等故障。针对振动应力、叶尖振幅和传声器阵列等测试方法复杂、成本高、周期长等特点,在风扇进气管道口布置单个传声器测量进口声信号,并对声信号进行时频分析,能够清晰识别出风扇叶盘的同步、非同步共振特征,结合计算结果分析获得共振转速和固有频率,与叶尖振幅测量结果相比最大误差分别为0.22%和0.42%,验证了该结果的准确性,为航空发动机风扇叶片盘设计和故障诊断提供了简单、有效的监测手段。 展开更多
关键词 风扇叶盘 共振特征 声信号 叶尖振幅 管道声模态
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