共查询到19条相似文献,搜索用时 390 毫秒
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本文利用特殊四阶时间平均多矩谱对任意均值乘性噪声与任意均值加性噪声共存,并且乘性噪声之间相关、乘性噪声与加性噪声之间相互独立的噪声背景下的三次非线性耦合进行了分析,该方法能够有效地估计出观测信号中参于三次非线性耦合的频率和耦合产生的频率.并且该方法无需限制乘性噪声与加性噪声的颜色和分布.最后,文中把此方法拓广到二维,用此二维四阶时间平均多矩谱方法分析了二维三次非线性耦合问题,同样取得了良好的效果.仿真实验验证了文中结论. 相似文献
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对于零均值独立乘性噪声背景下二维谐波的三次非线性耦合估计问题,由于缺乏理论支持及有效的计算方法,至今尚无有效的解决办法.本文首先分析了不同的噪声模型对谐波耦合分析所产生的影响,通过对原始采样数据进行平方预处理,改变了采样信号的信噪模型,利用新模型下噪声的统计特性及噪声间的相关特性,通过定义一种特殊四阶时间平均矩,首次解决了零均值独立噪声背景下谐波频率的二维三次非线性耦合问题.数学推导了该特殊四阶时间平均矩的矩多谱,理论证明了相应估计子渐进无偏性和一致性.理论分析和试验结果表明,该方法用于二维谐波的三次耦合分析时,不再需要对噪声的统计特性及噪声间的相关特性作任何限制. 相似文献
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由于单循环频率循环估计子估计性能对循环频率的选择有较大的依赖性,使其在实际应用中受到了较大的限制.为解决该问题,文章研究并给出了多循环频率循环时延估计方法,还详细推导得到了多循环频率估计子组的估计均方误差.在平稳高斯白噪声和慢变化时变高斯白噪声条件下对BPSK和QPSK信号的仿真结果表明,较高信噪比时(SNR>-6dB)循环估计子组的估计理论精度与仿真精度基本上是一致的,并且三循环频率循环估计子组估计性能要优于双循环频率循环估计子组,而双循环频率循环估计子组的估计性能要优于单循环频率循环估计子.仿真结果充分说明了文章理论分析的正确性,也说明了多循环频率循环时延估计方法的有效性及估计算子的稳健性. 相似文献
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从雷达等探测系统需要的频率估计出发,文中研究了利用循环平稳方法估计多个具有非零均值随机乘性噪声的复谐波信号参数的方法,并分析了其渐近统计性能,结果表明循环均值可用来恢复多个具有任意分布的非零均值有色乘性噪声的复谐波信号,且所得的谐波参数估计的均方差与相应的Cramer-Rao界具有相同的数量级。模拟结果验证了所得结果的正确性。 相似文献
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多个具有非零均值复乘性噪声的复谐波信号循环估计量的性能分析 总被引:2,自引:0,他引:2
从雷达等探测系统需要的频率估计出发,文中研究了利用循环平稳方法估计多个具有非零均值随机乘性噪声的复谱波信号参数的方法,并分析了其渐近统计性能,结果表明循环均值可用来恢复多个任意分布的非零均值有色乘性噪声的复谐波信号,且所得的谐波参数估计的均方差与相应的Cramer-Rao界具有相同的数量级。模拟结果验证了所得结果的正确性。 相似文献
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四阶累积量的递推估计及其应用 总被引:6,自引:0,他引:6
本文推导一种复数或实数零均值平稳随机过程的高阶累积量估计的递推算法,随机信号的“峰度”递推估计公式,在递推估计公式中引入了随时间变化的“修正”项,使得该递推算法还可适合非平稳过程高阶累积量的估计计算。并且,本文大量计算了多类型。多航速、多舰船辐射噪声的“峰度”值,分析了舰船辐射噪声特性。 相似文献
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The problem of estimating the frequencies of harmonics in multiplicative and additive noise is addressed. The cyclic mean (CM) can be used if the multiplicative noise has nonzero mean; the cyclic variance (CV) can be used whether or not the multiplicative noise has zero mean. This paper answers the following question: under what conditions should we use the CV instead of the CM? The criteria used are the ease of detection and the accuracy of estimation. The CV is preferable to the CM if the coherent to noncoherent harmonic power ratio is less than a threshold that depends on the first four cumulants; when the noises are colored, this threshold becomes frequency dependent. Third- and fourth-order cyclic statistics are also studied, and it is shown that they will always be outperformed either by the CM or CV when the multiplicative noise is symmetric 相似文献
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针对非零均值乘性噪声中的谐波恢复问题,本文提出一种基于广义协方差矩阵的乘性噪声中谐波个数和频率的估计方法。首先定义一类广义协方差并构造广义协方差矩阵,通过对广义协方差矩阵进行特征值理论分析,得到了非零均值乘性噪声中谐波分量个数与协方差矩阵特征值之间的内在联系,这个性质可以用来估计谐波分量个数。而且利用子空间旋转不变性技术,可以从协方差矩阵中估计出谐波的频率。本文所提方法对于乘性和加性噪声的颜色和分布均无任何假设,可以应用于任意分布和任意颜色的乘性和加性噪声中的谐波恢复。仿真实验表明,本文所提谐波恢复方法具有很高的频率分辨率。 相似文献
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噪声中的谐波恢复问题是信号处理领域的一个典型问题,在众多领域中有着广泛的应用。本文主要研究零均值乘性和加性噪声并存下的二维谐波信号频率估计问题,提出了一种基于数据矩阵的奇异值分解和子空间的旋转不变性的零均值乘性和加性噪声中的谐波频率的估计方法。乘性噪声为零均值情形下传统的估计方法往往难以直接应用或估计失效。本文利用谐波模型信号特征,通过对观测信号进行平方运算构造了一个数据矩阵。通过对数据矩阵的特征值进行理论分析,结合子空间旋转不变性,得到了零均值乘性和加性噪声中的谐波频率和数据矩阵之间的一种内在关系。这个性质可以用于零均值乘性和加性噪声并存下的二维谐波信号频率估计,并且所得的二维频率能自动配对。仿真实验验证了本文所提算法的有效性。 相似文献
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H.K. Sahoo P.K. DashN.P. Rath 《AEUE-International Journal of Electronics and Communications》2012,66(4):267-274
Mechanical vibration signals are always composed of harmonics of different order. A novel estimator is proposed for estimating the frequency of sinusoidal signals from measurements corrupted by White Gaussian noise with zero mean. Also low frequency sinusoidal signal is considered along with third and fifth order harmonics in presence of noise for estimating amplitudes and phases of different harmonics. The proposed estimator known as complex H∞ filter is applied to a noisy sinusoidal signal model. State space modeling with two and three state variables is used for estimation of frequency in presence of white noise. Various comparisons in terms of simulation results for time varying frequency reveal that the proposed adaptive filter has significant improvement in noise rejection and estimation accuracy. Comparison in performance between two and three states modeling is presented in terms of mean square error (MSE) under different SNR conditions .The computer simulations clearly indicate that two states modeling based on Hilbert transform performs better than three states modeling under high noisy condition. Frequency estimation performance of the proposed filter is also being compared with extended complex Kalman filter (ECKF) under same noisy conditions through simulations. 相似文献
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Polyspectral analysis of mixed processes and coupled harmonics 总被引:4,自引:0,他引:4
Guotong Zhou Giannakis G.B. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》1996,42(3):943-958
Polyspectral analysis of processes with mixed spectra is considered, and scaled polyperiodograms are introduced to clarify issues related to stationarity, ergodicity, and suppression of additive stationary noise in harmonic retrieval problems. Spectral and polyspectral approaches are capable of retrieving (un)coupled harmonics, not only when the harmonics have constant amplitudes, but also when they are observed in nonzero mean multiplicative noise. Fourier series polyspectra and asymptotic properties of scaled polyperiodograms provide general tools for higher order analysis of time series with mixed spectra. A single record phase coupling detector is derived to obviate the assumption of independent multiple records required by existing methods. The novelties are illustrated by simulation examples 相似文献
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噪声中的谐波恢复问题是信号处理领域的一个典型问题,在众多领域中有着广泛的应用。本文主要研究加性有色噪声中谐波频率的估计问题,提出了一种基于子空间旋转不变性的谐波频率的高分辨率估计方法。利用观测信号的自协方差函数构造了一个协方差矩阵,通过对协方差矩阵的特征值进行理论分析,结合子空间旋转不变性,得到了加性有色噪声中谐波的频率和协方差矩阵之间的一种内在联系。利用这个性质可以估计加性有色噪声中谐波的频率。本文方法对于有色噪声的模型无任何假设,而且对于噪声的分布也没有限制,对于高斯和非高斯有色噪声都适用。仿真实验验证了本文所提算法的有效性。 相似文献
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Multiplicative noise causes smearing of spectral lines and thus hampers frequency estimation relying on conventional spectral analysis. In contrast, cyclic mean and correlation statistics have proved to be useful for harmonic retrieval in the presence of multiplicative and additive noise of arbitrary color and distribution. Performance analysis of cyclic estimators is carried through both for nonzero and zero mean multiplicative noises. Cyclic estimators are shown to be asymptotically equivalent to certain nonlinear least squares estimators, and are also compared with the maximum likelihood ones. Large sample variance expressions of the cyclic estimators are derived and compared with the corresponding Cramer-Rao bounds when the noises are white Gaussian. It is demonstrated that previously well established results on constant amplitude harmonics are special cases of the present analysis. Simulations not only validate the large sample performance analysis, but also provide concrete examples regarding relative statistical efficiency of the cyclic estimators 相似文献