一类非均匀采样信号的内插重构算法

本针对多路Ａ／Ｄ交替采样存在的采样非均匀现象，分析了此类非均匀采样信号 ，进而推导出其内插重构算法，并通过计算机仿真验证了算法的正确性。该重构算法在工程实际中具有应用价值。  

非均匀采样时带通信号重建像函数的一种计算方法

在广义采样定理的信号模型的基础上，讨论了非均匀采样时带通信号的重建问题，导出了重建函数的傅里叶像的一种有效计算方法，最后给出了带通信号重建的计算机仿真实例。  

并行采样时多带信号重构函数的一种确定方法

在多带信号完全重构的基础上,推导出一种并行采样多带信号时重构插值函数的确定方法.此方法是根据多带信号的频谱特点将重构插值函数的确定转化为一次线性方程组的求解.通过实例验证了重构插值函数确定方法的有效性,并进一步得出了此方法获得重构插值函数可保证总采样频率最小.  

On the phase interpolation problem — A brief review and some new results

Reconstruction of a signal from the phase of its Fourier transform is important and useful in a variety of practical applications. In this paper, we give a brief review of the previous results and develop some new ones pertaining to the phase-only reconstruction problem. The review includes conditions under which the signal is uniquely specified by its Fourier transform phase and some algorithms for performing the reconstruction. New results consist of an extension of a previous technique and an explicit formula for reconstruction. A number of potential applications of the reconstruction techniques are briefly mentioned in the concluding section. Throughout this paper, reference to the phase or magnitude of the signal should be interpreted, respectively, as the phase or magnitude of theft of the signal.  

Bandlimited rational models for signal reconstruction

A rational model is proposed for reconstruction of bandlimited signals from successive observations, bandlimits, and knowledge of signal peak location. The parameters of the model may be estimated from the singular vectors of a certain double-Hankel matrix constructed from this information. In contrast to the currently popular minimum-energy approach, which has limited spectral resolution and is sensitive to noise, high spectral resolution is possible with the rational model because of its pole-zero nature. To reduce the sensitivity of the rational reconstruction to noise and modelling errors, rank reduction of the double-Hankel matrix via singular value decomposition is suggested. The singular values of the matrix provide estimates of the error in modelling the data with rational models of different orders, and so the singular value distribution can be used to select model order. This work was partially supported by SDIO/IST under contract DAAL 03-86-0111 administered by the US Army Research Office, by the Bell Communication Research’s Graduate Study Program, and by Cray Research Inc. under grants DMS9880010SC and ECS890002SC and utilized by the Cray X-MP/48 at the National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign.  

桥梁动力测试信号的自适应分解与重构

针对桥梁结构动力测试信号噪声水平高、难以分离结构有效信号的特点,在总体平均经验模态分解方法和主成分分析的基础上,建立了自适应分解与重构方法。对经验模态分解结果的模态混叠现象进行深入分析,利用白噪声概率密度函数的均匀性对模态混叠模式一进行了改进,基于相关性分析改进了模态混叠模式二,改进后的分解方法在计算效率和分解精度上均有较大提升;随后对所有分解获得的固有模态函数进行多尺度主成分分析,实现降噪和选择并重构测试信号。分别用模拟信号和实际桥梁测试信号对所提方法的有效性进行了验证。结果表明:改进后的信号自适应分解和重构方法能在降噪的同时,有效地提取桥梁结构信息,可用于实际桥梁结构的动力测试分析中。  

水下报文通信抗干扰方法

针对水声通信中的衰减信道和多途效应对报文通信的影响,利用混沌编码方式以获取处理增益,并利用拷贝相关器对信道进行估值的基础上,提出了用相干重置的方法对多途效应加以利用,以降低误码率。仿真结果表明,相干重置的方法相对于直接相关解码方法具有更低的误码率。由此可见,以上的方法对减少多途干扰的影响是有明显的效果的。水声通信一般都采取抑制多途的方法,以减少对接收信号的干扰,从另一角度出发,创新性地提出了利用多途干扰的方法,并通过仿真证明其有效性,这对降低水下报文通信的误码率是有重要意义的。  

使用合成滤波器组的SAS方位向非均匀采样信号重构

针对多子阵合成孔径声纳（Synthetic Aperture Sonar,SAS）在方位向上非均匀采样对后续成像处理带来的方位向失真的影响,给出了基于滤波器组的方位向非均匀采样信号重构算法。该算法利用SAS方位向周期性非均匀采样信号与经过分析滤波器组的信号之间的相似性,将周期非均匀采样信号通过合成滤波器组进行重构得到均匀采样信号。该算法相对于传统时域重构和频域重构方法,具有点目标冲激响应主瓣宽度更窄,旁瓣电平更低的优点。通过仿真与对湖试数据的处理,该算法在多子阵SAS上的有效性与优势得到验证。  

一种新的基于声信号的故障分类算法

提出采用相空间重构与高斯混合模型相结合的方法，利用声信号对设备进行故障分类．此方法首先将一维声信号时间序列进行相空间重构，在高维相空间展示各故障状态下的动力学特性，然后通过最大期望值算法建立相空间的高斯混合模型，最后采用贝叶斯分类算法进行故障的识别．从齿轮故障试验台上采集常见齿轮故障的声信号并进行分类实验，验证了该方法的有效性．