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
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
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
We investigate two-user sum-rate capacity for Poisson channel considering practical photon-counting receiver,including finite sampling rate and dead time.The sum-rate capacity reduction due to photon-counting loss is ...We investigate two-user sum-rate capacity for Poisson channel considering practical photon-counting receiver,including finite sampling rate and dead time.The sum-rate capacity reduction due to photon-counting loss is characterized and compared with that of continuous Poisson channel.We show that the sum-rate capacity with non-perfect receiver approaches the capacity of continuous time Poisson channel as the sampling time and dead time both approach zero.For optimal transmission strategy,we demonstrate three possible transmission strategies,including only one active user and two active users.In addition,we study the special case of identical peak power constraint for each user.We adopt majorization method to demonstrate that the optimal duty cycle for the two users must be the same and unique.Furthermore,we analyze the sum-rate capacity for multiple input single output(MISO)multiple-access channel(MAC).We propose a sufficient condition on dead time where the sum-rate capacity of the Poisson MISO-MAC is equivalent to that of single input single output,and the equivalence would not hold for sufficient large peak power or dead time.The theoretical capacity results are validated by numerical results.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
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。
基金This work was supported by National Key Research and Development Program of China under Grant 2018YFB1801904Key Program of National Natural Science Foundation of China under Grant 61631018Key Research Program of Frontier Sciences of CAS under Grant QYZDYSSW-JSC003。
文摘We investigate two-user sum-rate capacity for Poisson channel considering practical photon-counting receiver,including finite sampling rate and dead time.The sum-rate capacity reduction due to photon-counting loss is characterized and compared with that of continuous Poisson channel.We show that the sum-rate capacity with non-perfect receiver approaches the capacity of continuous time Poisson channel as the sampling time and dead time both approach zero.For optimal transmission strategy,we demonstrate three possible transmission strategies,including only one active user and two active users.In addition,we study the special case of identical peak power constraint for each user.We adopt majorization method to demonstrate that the optimal duty cycle for the two users must be the same and unique.Furthermore,we analyze the sum-rate capacity for multiple input single output(MISO)multiple-access channel(MAC).We propose a sufficient condition on dead time where the sum-rate capacity of the Poisson MISO-MAC is equivalent to that of single input single output,and the equivalence would not hold for sufficient large peak power or dead time.The theoretical capacity results are validated by numerical results.
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。
