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1.
In echo cancellers for teleconference systems, the serious problem of double-talk still exists. The authors propose a new algorithm where, for tap adaptation, the gradient is searched by the input correlation functions. A computer simulation of the proposed CLMS algorithm shows robust performance in double-talk situations 相似文献
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《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1985,73(6):1137-1138
In this letter, we propose a frequency-weighted block LMS (FWBLMS) algorithm that is based on minimization of the frequency-weighted block mean-squared error. The FWBLMS algorithm has an important advantage over the time-domain LMS algorithm in that it can be designed with different frequency weighting on error signal depending on the relative significance of various frequency bands. Application of the FWBLMS algorithm in adaptive linear prediction of speech is discussed. 相似文献
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采用部分更新最小均方(LMS)算法和重叠保留的块信号频域处理结构,针对现场可编程门阵列(FPGA)的硬件实现平台,提出了时频混合部分更新块LMS和周期性块部分更新LMS均衡算法结构。2种新结构均能有效降低均衡算法的实现复杂度。步长收敛条件分析和数值仿真结果表明,新结构能够在适当调整更新步长的情况下,有效跟踪缓变信道的变化,实现与完整块LMS算法相当的性能,能够有效解决高速数据传输中的均衡复杂度过高的问题。 相似文献
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This paper has two contributions. First, the concept of the generalized sliding fast Fourier transform (GSFFT) as an efficient implementation of the hopping FFT is introduced. Application of the GSFFT is broad and not limited to what has been considered in this paper. The frequency domain block LMS (FBLMS) adaptive filters are then revised, and their implementations for block lengths less than the length of the adaptive filter are studied. The GSFFT and the available pruned FFTs are used to give an efficient implementation of these filters. In the particular case of the block length equal to one, where the FBLMS algorithm reduces to the frequency domain LMS (FLMS) algorithm, it is shown that the latter can be implemented with the order of M complexity, where M is the length of the adaptive filter 相似文献
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DeBrunner V.E. Dayong Zhou 《IEEE transactions on circuits and systems. I, Regular papers》2006,53(3):653-661
The filtered-error LMS (FELMS) algorithms are widely used in multi-input and multi-output control (MIMO) active noise control (ANC) systems as an alternative to the filtered-x LMS (FXLMS) algorithms to reduce the computational complexity and memory requirements. However, the available FELMS algorithms introduce significant delays in updating the adaptive filter coefficients that slow the convergence rate. In this paper, we introduce a novel algorithm called the hybrid filtered-error LMS algorithm (HFELMS) which, while still a form of the FELMS algorithm, allows users to have some freedom to construct the error filter that guarantees its convergence with a sufficiently small step size. Without increasing the computational complexity, the proposed algorithm can improve the control system performance in one of several ways: 1) increasing the convergence rate without extra computation cost; 2) reducing the remaining noise mean square error (MSE); or 3) shaping the excess noise power. Simulation results show the effectiveness of the proposed method. 相似文献
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Analysis of constrained LMS algorithm with application to adaptive beamforming using perturbation sequences 总被引:1,自引:0,他引:1
Adaptive antenna array processing employing a constrained least mean square (LMS) algorithm requires an unbiased estimate of the gradient of the output power with respect to the array weights. There are a number of schemes for obtaining an unbiased estimate of this gradient. Though in each case the estimated gradient is unbiased, the covariance of the estimated gradient with each method is different and thus the transient and the steady state behavior of the constrained algorithm is different in each case. The transient and the steady state behavior of the weight covariancc matrix is analyzed, exact expressions for the misadjustment are derived, and a comparison of the performance of the algorithm is presented when the required gradient is estimated by different schemes. The schemes considered include gradient estimation when all the array signals are accessible as well as gradient estimation using perturbation sequences for eases when the array signals are inaccessible. The necessary and the sufficient condition for the diagonlization of the weight covarience matrix is also derived. 相似文献
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成像器稳定跟踪平台的稳定回路设计是一种高精度、高动态响应的伺服回路设计,为实现较好的控制特性,提出了一种基于LMS算法的Adaline网络参数自适应控制方法,根据被控对象的参数变化,实时调整控制器的参数,由于算法相对简单,满足实际工程应用的要求。为了避免自适应算法运算对系统响应快速性的影响,设计了基于常规控制和自适应控制的双模态控制器结构,根据实际工作条件,进行控制策略的实时切换,既保证了系统响应的快速性,又保证了控制精度。实验结果表明,采用该方法实现的稳定回路具有良好的动态和静态特性。 相似文献
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The least mean square (LMS) algorithm is known to converge in the mean and in the mean square. However, during short time periods, the error sequence can blow up and cause severe disturbances, especially for non-Gaussian processes. The paper discusses potential short time unstable behavior of the LMS algorithm for spherically invariant random processes (SIRP) like Gaussian, Laplacian, and K0. The result of this investigation is that the probability for bursting decreases with the step size. However, since a smaller step size also causes a slower convergence rate, one has to choose a tradeoff between convergence speed and the frequence of bursting 相似文献
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The least mean square (LMS) algorithm is investigated for stability when implemented with two's complement quantization. The study is restricted to algorithms with periodically varying inputs. Such inputs are common in a variety of applications, and for system identification, they can always be generated as shown with an example. It is shown that the quantized LMS algorithm is just a special case of a quantized periodically shift-varying (PSV) filter. Two different sufficient conditions are obtained for the bounded input bounded output (BIBO) stability of the PSV filter. When the filter is BIBO stable, two different bounds on the filter output are also derived. These conditions and bounds are then applied to the quantized LMS algorithm. The results are illustrated with examples. 相似文献
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A method to optimize the step size of the LMS algorithm when it is used to identify a time-varying system is proposed. The formulation allows uncertain specifications of the input excitation and the plant variation. The method is robust in that it minimizes the mean square error for the worst-case data of these variables 相似文献
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Hu Jin-Lin Ma Yan Lin Shi-Ming Wang Wen-Bing 《Electronics letters》1997,33(10):825-826
The authors present a new algorithm: the multiplaten Z-buffer algorithm. By employing a geometry based on this algorithm we can speed up the process of ray tracing, which is used to calculate the multiple scattering of a complex object. Comparison with the experimental results shows this algorithm to be effective 相似文献
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《IEEE signal processing letters》2010,17(3):229-232
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Analysis of the frequency-domain block LMS algorithm 总被引:7,自引:0,他引:7
We present a new analysis of the frequency-domain block least-mean-square (FBLMS) algorithm. An earlier analysis uses a mapping of the frequency-domain information to the time-domain before proceeding with the analysis of the algorithm. We present a direct analysis of the FBLMS algorithm in the frequency domain. As compared with the previous analysis, the new analysis is easier to follow. It is also more rigorous than the previous works and gives a better insight to the effect of various processing components in the algorithm structure on its convergence behavior. In particular, we show how the transformation of input samples to the frequency domain, combined with the effect of the involved windowing matrices, and step-normalization affect the convergence behavior of both constrained and unconstrained versions of the FBLMS algorithm. We also report a procedure for derivation of misadjustment equations of various versions of the FBLMS algorithm 相似文献
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The authors consider the stability properties of the conventional continuous-time least mean square algorithm. The algorithm for the case of stationary ergodic inputs is investigated and a necessary and sufficient condition for exponential almost-sure convergence is presented. This condition is shown to be less restrictive than the well-known persistency of excitation condition. Also, the authors point out and clarify an apparently common error regarding the connections between persistency of excitation and positive definite autocorrelation in stationary ergodic vector waveforms 相似文献
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In this paper, a new and stable subgridding algorithm is proposed for three-dimensional problems which provides subgridding in both space and time. The concept of an equivalent-circuit representation and a novel leapfrog time integration scheme is used to ensure that the algorithm is stable and efficient. Practical applications of this algorithm in the characterization of arbitrarily filled dielectric resonators are reported 相似文献
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针对电磁辐射现场测试被测设备信号和干扰未知的情况,提出了一种基于频域块最小均方算法的实时虚拟暗室测试方法。该方法采用双通道接收机,根据测试通道和背景通道中干扰信号的相关性设计自适应滤波器,在频域对背景通道信号滤波以趋近测试通道中的干扰分量,采用瞬时双通道信号迭代更新滤波器系数,滤波器系数收敛后系统输出中只有被测设备信号。仿真与分析表明,该方法在背景通道有无被测设备信号泄露的情况下都能有效抑制干扰,与基于时域最小均方算法的方法相比,在滤波器长度相同的情况下其计算复杂度更低,适用于实时现场测试。 相似文献