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基于最小二乘(LMS)统计算法的自适应线性元件(Adaline)神经网络是非线性分类的重要工具之一。从计算机仿真的角度研究随机逼近LMS学习方法的特点,从步长设置、收敛性、收敛速度、算法抗噪性、判断的准确率等多个参量评估随机逼近法的性能。仿真结果表明,对于不同的初始步长设置,神经元完成学习任务的训练时间不同;在保证学习收敛性的前提下,步长越大,收敛速度越快,但收敛的稳定性变差。权矢量的初始值设置对学习的收敛性没有影响。 相似文献
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Dragos Nicolae Vizireanu 《International Journal of Electronics》2013,100(11):1175-1181
The principles for the development of portable instrumentation equipment (multimeters, frequency meters, etc.) using quantised sine signals, with a common unknown fixed frequency, and an estimation algorithm implemented on digital signal processors (DSPs) are described. An unknown internal sine signal is generated. For measurements, analog to digital converters (ADCs) acquire multiple samples of sine signals, which are quantised and transmitted to the DSP. A precise quantised sine signal, with a common unknown fixed frequency, signal estimation algorithm, for DSP-based instrumentation, is presented. An iterative process is performed to obtain amplitudes, phases, dc components, common frequency and to control the ADC number of bits. Final solutions depend on the initial values, obtained using different classical estimation algorithms. The accuracy of the initial values of iterations and the number of used points have a large influence on the speed of convergence. The algorithm stops when quantisation conditions are satisfied. 相似文献
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针对低信噪比下信号源个数估计问题,改进基于特征向量与阵列流形正交性的这种目前信号源个数估计效果很好的算法。该改进主要在于引入一个更能去噪的门限准则,结合原来的盲波束形成方法,最后得到一种基于阵列信号处理的信号源个数估计算法。仿真结果证实在低信噪比下,文中所提方法在等功率信号入射时比原方法有效,而且在不等功率信号入射时效果也比原方法好。 相似文献
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Tang Bin 《电子科学学刊(英文版)》1998,15(3):233-239
Based on time delay technology and MUSIC algorithm, a novel estimating multiple frequencies approach of signal with sampling rate which is least Nyquist sampling rate is presented in this paper. With choosing delay time properly, the estimated frequencies are unambiguous. Computer simulation confirms its availability. 相似文献
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R. Punchalard 《AEUE-International Journal of Electronics and Communications》2014,68(11):1112-1118
Based on power spectral density (PSD) analytical technique, mean square error (MSE) (or variance) of the frequency estimate of a first-order complex adaptive IIR notch filter (ANF) using modified complex plain gradient (MCPG) algorithm is investigated in this paper. The steady-state expression for MSE is derived in closed form. A quantitative analysis for the estimation MSE has been carried out. It has been revealed that the MSE of frequency estimate is independent of an input frequency of a complex sinusoid. In addition, computer simulations are treated to corroborate the theoretical analysis and the relationships between MSE and system parameters are shown. 相似文献
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本文围绕电力设备的状态检修进行研究,分析时变停运模型的原理及特点,结合其在状态检修的应用效果,分析其适用性. 相似文献
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PADEC算法中引入已知波形信号源的信息,使得相干多径信号的DOA估计性能大大提高,而DEESE算法异于传统空间平滑算法的独特去相关策略,使它在低信噪比、天线阵阵元数较少时有着良好的DOA估计性能.结合这两种算法各自的优点,将DEESE算法的去相关策略应用于PADEC算法中,形成PADEC-DEESE算法.计算机仿真结果表明,PADEC-DEESE算法完全能够实现相干多径信号的DOA估计,并在天线阵阵元数较少、低信噪比情况下的DOA估计精度优于PADEC、DEESE及传统的MUSIC-SS算法. 相似文献
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基于先验知识模型,设计了基于信道剩余空闲时间估计的动态频谱接入算法:每个次用户根据感知历史维护信道剩余空闲时间的估计向量并周期进行更新,每个时隙开始时次用户选择剩余空闲时间估计最大的信道接入。对动态频谱接入算法的适应性问题进行了分析,并求得了次用户的最优传输时间长度。仿真结果表明,在给定的参数下,新算法的信道利用率比其他算法提高约5%-10%,同时对主用户的干扰保持最低。 相似文献
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针对传统波达方向估计算法在低信噪比条件下性能表现不佳的问题,本文提出了一种基于改进多信号分类的波达方向估计算法。本文首先对多信号分类算法的不足进行分析,并采用时间平滑技术构建相关矩阵,然后采用相关矩阵建立空间谱函数达到波达方向估计,最后采用仿真实验对算法的性能进行测试。结果表明,本文算法可以快速准确的估计出多个信号的波达方向,降低了波达方向估计误差,而且性能远远优于其它改进多信号分类算法。 相似文献
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This paper investigates the relation between the nonstationary sound source and the frequency domain magnitude ratio of two microphones based on short-term frequency analysis. The fluctuation level of nonstationary sound sources is modeled by the exponent of polynomials from the concept of moving pole model. According to this model, the sufficient condition for utilizing the fluctuation level and magnitude ratio to estimate the time delay between two microphones is suggested. Simulation results are presented to show the performance of the suggested method. 相似文献
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A numerically efficient algorithm for estimating the time delay from observations of a stationary narrowband signal and its delayed version is investigated. Quadrature sampling, a variant of bunched sampling, is applied to estimate samples of the quadrature components of the cross-covariance function of the two signals. The baseband magnitude squared of this function can be maximized for time delay estimation. Because the time delay is unknown, the baseband cross-covariance function cannot be interpolated from the estimated samples. Numerical maximization of the samples' magnitude squared and quadratic interpolation, however, results in a reasonable time delay estimate. 相似文献
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Han Zhang Haixia Cui Daru Pan Yide Wang 《Wireless Communications and Mobile Computing》2014,14(9):891-904
An approach of superimposed training (ST)‐aided time‐varying (TV) channel estimation for multiple‐input multiple‐output orthogonal frequency division multiplexing systems is presented. By modeling the TV channel with the truncated discrete basis expansion model, a two‐step approach is adopted to estimate the TV channel. In addition, the mean square error (MSE) of the proposed channel estimation is analyzed, and its closed‐form expression is derived, which is a function of the data‐to‐ST power ratio. Using the developed channel MSE, we case the problem of ST power‐allocation by minimizing the lower bound on the average channel capacity. To enhance the performance of channel estimation, a low‐complexity decision feedback mechanism is introduced to iteratively mitigate the unknown data interference. Numerical results verify the performances of the proposed approach. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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Bo Li 《International Journal of Communication Systems》2013,26(7):853-862
An improved algorithm is presented for a signal's direction of arrival estimation to reduce the computational complexity of the existing modified multiple signal classification (MMUSIC) algorithm. In this paper, FFT algorithm is introduced to narrow the searching range of the direction angle. Afterwards, a compromise approach‐based SVD and orthogonal–triangular decomposition takes the place of traditional double SVDs. Then, during matrix calculation, the noise subspace is achieved for the signal's direction of arrival. Finally, the system simulation demonstrates the efficiency and reliability of this novel MMUSIC algorithm. Compared with the existing algorithm, MMUSIC effectively saves the computational complexity with the approximation estimation performance. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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估计时变幅值复线性调频信号的循环平稳方法及其统计性能分析 总被引:2,自引:0,他引:2
本文分析了利用循环平稳方法估计离散时间变幅值复线性调频(LFM)信号参数的渐近统计性能,表明所得的时变幅值LFM信号参数估计的均方差与相应的Cramer-Rao界关于T的收敛性具有相同的数量级。模拟结果验证了所得结果的正确性。 相似文献
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