压缩感知是一种亚奈奎斯特率信息采样方法。基于压缩感知的符号检测方法通常先将亚奈奎斯特率样本重构为奈奎斯特率样本,然后再依据传统符号检测的原理检测接收符号。本文针对基于重构的压缩感知符号检测方法采样率过高的问题,研究广义...压缩感知是一种亚奈奎斯特率信息采样方法。基于压缩感知的符号检测方法通常先将亚奈奎斯特率样本重构为奈奎斯特率样本,然后再依据传统符号检测的原理检测接收符号。本文针对基于重构的压缩感知符号检测方法采样率过高的问题,研究广义似然比检测和信息采样样本之间的关系,提出了一种不需要重构奈奎斯特率样本的压缩检测方法。该方法首先通过双通道时延结构分离接收信号的参考部分和信息符号部分,然后依据两部分信号的稀疏相关特性,对亚奈奎斯特率接收符号进行检测。实验结果表明本文提出的方法能够有效地抵抗多径衰弱和符号间干扰(Inter Symbol Interference,ISI)。展开更多
针对欠采样脉冲多普勒雷达信号参数估计中已有方法抗噪性差、顺序参数估计方法中后续参数估计受前面参数估计精度影响严重等问题,该文提出一种基于有限新息率(Finite Rate of Innovation,FRI)采样的频域时延-多普勒2维聚焦(FD2TF)算法...针对欠采样脉冲多普勒雷达信号参数估计中已有方法抗噪性差、顺序参数估计方法中后续参数估计受前面参数估计精度影响严重等问题,该文提出一种基于有限新息率(Finite Rate of Innovation,FRI)采样的频域时延-多普勒2维聚焦(FD2TF)算法。在该算法中,利用FRI采样结构能够以低于奈奎斯特采样频率的速率获得信号的一系列傅里叶系数,通过频域2维聚焦过程能够同时估计时延和多普勒参数,避免了参数顺序估计中误差累积的问题,理论分析证明了该算法能够大幅提升采样信号的信噪比,提高算法抗噪性和鲁棒性。在2维聚焦算法的基础上该文还提出了基于逆傅里叶变换的2维聚焦简化算法,在提高参数估计网格密度的同时,大大减低了2维聚焦算法的计算量。仿真和对比实验结果证明了该方法的有效性和良好的抗噪性。展开更多
To achieve sparse sampling on a coded ultrasonic signal,the finite rate of innovation(FRI)sparse sampling technique is proposed on a binary frequency-coded(BFC)ultrasonic signal.A framework of FRI-based sparse samplin...To achieve sparse sampling on a coded ultrasonic signal,the finite rate of innovation(FRI)sparse sampling technique is proposed on a binary frequency-coded(BFC)ultrasonic signal.A framework of FRI-based sparse sampling for an ultrasonic signal pulse is presented.Differences between the pulse and the coded ultrasonic signal are analyzed,and a response mathematical model of the coded ultrasonic signal is established.A time-domain transform algorithm,called the high-order moment method,is applied to obtain a pulse stream signal to assist BFC ultrasonic signal sparse sampling.A sampling of the output signal with a uniform interval is then performed after modulating the pulse stream signal by a sampling kernel.FRI-based sparse sampling is performed using a self-made circuit on an aluminum alloy sample.Experimental results show that the sampling rate reduces to 0.5 MHz,which is at least 12.8 MHz in the Nyquist sampling mode.The echo peak amplitude and the time of flight are estimated from the sparse sampling data with maximum errors of 9.324%and 0.031%,respectively.This research can provide a theoretical basis and practical application reference for reducing the sampling rate and data volume in coded ultrasonic testing.展开更多
文摘压缩感知是一种亚奈奎斯特率信息采样方法。基于压缩感知的符号检测方法通常先将亚奈奎斯特率样本重构为奈奎斯特率样本,然后再依据传统符号检测的原理检测接收符号。本文针对基于重构的压缩感知符号检测方法采样率过高的问题,研究广义似然比检测和信息采样样本之间的关系,提出了一种不需要重构奈奎斯特率样本的压缩检测方法。该方法首先通过双通道时延结构分离接收信号的参考部分和信息符号部分,然后依据两部分信号的稀疏相关特性,对亚奈奎斯特率接收符号进行检测。实验结果表明本文提出的方法能够有效地抵抗多径衰弱和符号间干扰(Inter Symbol Interference,ISI)。
文摘针对欠采样脉冲多普勒雷达信号参数估计中已有方法抗噪性差、顺序参数估计方法中后续参数估计受前面参数估计精度影响严重等问题,该文提出一种基于有限新息率(Finite Rate of Innovation,FRI)采样的频域时延-多普勒2维聚焦(FD2TF)算法。在该算法中,利用FRI采样结构能够以低于奈奎斯特采样频率的速率获得信号的一系列傅里叶系数,通过频域2维聚焦过程能够同时估计时延和多普勒参数,避免了参数顺序估计中误差累积的问题,理论分析证明了该算法能够大幅提升采样信号的信噪比,提高算法抗噪性和鲁棒性。在2维聚焦算法的基础上该文还提出了基于逆傅里叶变换的2维聚焦简化算法,在提高参数估计网格密度的同时,大大减低了2维聚焦算法的计算量。仿真和对比实验结果证明了该方法的有效性和良好的抗噪性。
基金The National Natural Science Foundation of China (No.51375217)。
文摘To achieve sparse sampling on a coded ultrasonic signal,the finite rate of innovation(FRI)sparse sampling technique is proposed on a binary frequency-coded(BFC)ultrasonic signal.A framework of FRI-based sparse sampling for an ultrasonic signal pulse is presented.Differences between the pulse and the coded ultrasonic signal are analyzed,and a response mathematical model of the coded ultrasonic signal is established.A time-domain transform algorithm,called the high-order moment method,is applied to obtain a pulse stream signal to assist BFC ultrasonic signal sparse sampling.A sampling of the output signal with a uniform interval is then performed after modulating the pulse stream signal by a sampling kernel.FRI-based sparse sampling is performed using a self-made circuit on an aluminum alloy sample.Experimental results show that the sampling rate reduces to 0.5 MHz,which is at least 12.8 MHz in the Nyquist sampling mode.The echo peak amplitude and the time of flight are estimated from the sparse sampling data with maximum errors of 9.324%and 0.031%,respectively.This research can provide a theoretical basis and practical application reference for reducing the sampling rate and data volume in coded ultrasonic testing.
