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
为了完成线性调频(linear frequency modulation,LFM)信号的稀疏采样,并利用稀疏数据对原始信号参数进行估计,本文提出了一种基于Z变换和改进有限新息率(finite rate of innovation,FRI)的LFM信号参数估计方法。以Z变换理论为基础,设计...为了完成线性调频(linear frequency modulation,LFM)信号的稀疏采样,并利用稀疏数据对原始信号参数进行估计,本文提出了一种基于Z变换和改进有限新息率(finite rate of innovation,FRI)的LFM信号参数估计方法。以Z变换理论为基础,设计了一种数学模型,一旦信号能够表达成该数学模型的结构形式,就能通过Z变换和零化滤波器的方法估计信号参数。然后,利用了自相关延迟的FRI结构对LFM信号采样,该结构不仅完成了LFM信号的稀疏采样,而且稀疏采样结果能够与数学模型结构相符。在理论上通过数学论证的方式证明了所提方法能够用于获取LFM信号参数信息,并通过仿真和实测数据验证了所提方法的有效性,理论和实验结果表明该方法只需要4个采样点就能实现对LFM信号的参数估计,并且实验中的参数估计误差均在3%以内,极大的提高有限新息率采样的参数估计效率。展开更多
Measurement and reconstruction of wireless pulses is an important scheme in wireless ultra wide band (UWB) technology. In contrary to the band-limited analog signals, which can be recovered from evenly spaced samples,...Measurement and reconstruction of wireless pulses is an important scheme in wireless ultra wide band (UWB) technology. In contrary to the band-limited analog signals, which can be recovered from evenly spaced samples, the reconstruction of the UWB pulses is a more demanding task. In this work we describe an exponential sampling filter (ESF) for measurement and reconstruction of UWB pulses. The ESF is constructed from parallel filters, which has exponentially descending impulse response. A pole cancellation filter was used to extract the amplitudes and time locations of the UWB pulses from sequentially measured samples of the ESF output. We show that the amplitudes and time locations of p sequential UWB pulses can be recovered from the measurement of at least 2p samples from the ESF output. For perfect reconstruction the number of parallel filters in ESP should be 2p. We study the robustness of the method against noise and discuss the applications of the method.展开更多
有限新息率(Finite Rate of Innovation,FRI)框架是针对非带限信号进行采样与重构的有效理论,然而该方法对脉冲频谱有特殊要求,对于复杂脉冲波形,方法可能失效。针对该问题,该文基于指数再生核设计了一种FRI采样与重构系统,其突出优势...有限新息率(Finite Rate of Innovation,FRI)框架是针对非带限信号进行采样与重构的有效理论,然而该方法对脉冲频谱有特殊要求,对于复杂脉冲波形,方法可能失效。针对该问题,该文基于指数再生核设计了一种FRI采样与重构系统,其突出优势是能够通过合理地设置再生核参数来增加对复杂波形的适应性。另一方面,考虑到系统稳定性和采样核的实现,再生核参数还需要满足额外的约束条件,文中具体分析了这些约束因素,并给出了设置方法。最后以线性调频相位编码混合波形为例进行了仿真,结果验证了该文方法的有效性。展开更多
在有限新息率(Finite Rate of Innovation,FRI)采样框架中,指数再生核具有良好的时域有限支撑特性,因此被广泛用作采样核。但是这一过程会将信号中的白噪声变为有色噪声,严重影响重构性能。为此,该文利用指数再生形式能够在卷积运算中...在有限新息率(Finite Rate of Innovation,FRI)采样框架中,指数再生核具有良好的时域有限支撑特性,因此被广泛用作采样核。但是这一过程会将信号中的白噪声变为有色噪声,严重影响重构性能。为此,该文利用指数再生形式能够在卷积运算中得以保留的特性,提出一种改进的指数再生采样核,其对应的系数矩阵能够保持噪声的统计特性,进而保证重构算法性能。仿真实验表明该文方法能够有效提升重构性能。展开更多
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
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.
文摘为了完成线性调频(linear frequency modulation,LFM)信号的稀疏采样,并利用稀疏数据对原始信号参数进行估计,本文提出了一种基于Z变换和改进有限新息率(finite rate of innovation,FRI)的LFM信号参数估计方法。以Z变换理论为基础,设计了一种数学模型,一旦信号能够表达成该数学模型的结构形式,就能通过Z变换和零化滤波器的方法估计信号参数。然后,利用了自相关延迟的FRI结构对LFM信号采样,该结构不仅完成了LFM信号的稀疏采样,而且稀疏采样结果能够与数学模型结构相符。在理论上通过数学论证的方式证明了所提方法能够用于获取LFM信号参数信息,并通过仿真和实测数据验证了所提方法的有效性,理论和实验结果表明该方法只需要4个采样点就能实现对LFM信号的参数估计,并且实验中的参数估计误差均在3%以内,极大的提高有限新息率采样的参数估计效率。
文摘Measurement and reconstruction of wireless pulses is an important scheme in wireless ultra wide band (UWB) technology. In contrary to the band-limited analog signals, which can be recovered from evenly spaced samples, the reconstruction of the UWB pulses is a more demanding task. In this work we describe an exponential sampling filter (ESF) for measurement and reconstruction of UWB pulses. The ESF is constructed from parallel filters, which has exponentially descending impulse response. A pole cancellation filter was used to extract the amplitudes and time locations of the UWB pulses from sequentially measured samples of the ESF output. We show that the amplitudes and time locations of p sequential UWB pulses can be recovered from the measurement of at least 2p samples from the ESF output. For perfect reconstruction the number of parallel filters in ESP should be 2p. We study the robustness of the method against noise and discuss the applications of the method.
文摘有限新息率(Finite Rate of Innovation,FRI)框架是针对非带限信号进行采样与重构的有效理论,然而该方法对脉冲频谱有特殊要求,对于复杂脉冲波形,方法可能失效。针对该问题,该文基于指数再生核设计了一种FRI采样与重构系统,其突出优势是能够通过合理地设置再生核参数来增加对复杂波形的适应性。另一方面,考虑到系统稳定性和采样核的实现,再生核参数还需要满足额外的约束条件,文中具体分析了这些约束因素,并给出了设置方法。最后以线性调频相位编码混合波形为例进行了仿真,结果验证了该文方法的有效性。
文摘在有限新息率(Finite Rate of Innovation,FRI)采样框架中,指数再生核具有良好的时域有限支撑特性,因此被广泛用作采样核。但是这一过程会将信号中的白噪声变为有色噪声,严重影响重构性能。为此,该文利用指数再生形式能够在卷积运算中得以保留的特性,提出一种改进的指数再生采样核,其对应的系数矩阵能够保持噪声的统计特性,进而保证重构算法性能。仿真实验表明该文方法能够有效提升重构性能。
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)。
