This paper presents a stochastic analysis of the leaky filtered-X least-mean-square (LFXlms) algorithm. The version with leakage of the adaptive algorithm is used in practical implementations aiming to reduce undesira...
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This paper presents a stochastic analysis of the leaky filtered-X least-mean-square (LFXlms) algorithm. The version with leakage of the adaptive algorithm is used in practical implementations aiming to reduce undesirable effects due to numerical errors in finite-precision machines, overload of the secondary source, among others. Based on new analysis assumptions, instead of the ordinary independence theory frequently used in classical lms analysis, an analytical model for the first and second moments of the adaptive filter weights has been derived. In addition, the proposed theoretical models consider the situation in which the secondary path is imperfectly modeled. Experimental results demonstrate the accuracy of the proposed model as compared with the classical analysis.
The least mean squares (lms) algorithm has been widely used for adaptive filtering because of easily implementing at a computational complexity of O(2N) where N is the number of taps. The drawback of the lms algorithm...
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The least mean squares (lms) algorithm has been widely used for adaptive filtering because of easily implementing at a computational complexity of O(2N) where N is the number of taps. The drawback of the lms algorithm is that its performance is sensitive to the scaling of the input. The normalized lms (Nlms) algorithm solves this problem on the lms algorithm by normalizing with the sliding-window power of the input;however, this normalization increases the computational cost to O(3N) per iteration. In this work, we derive a new formula to strictly perform the Nlms algorithm at a computational complexity of O(2N), that is referred to as the C-Nlms algorithm. The derivation of the C-Nlms algorithm uses the H-infinity framework presented previously by one of the authors for creating a unified view of adaptive filtering algorithms. The validity of the C-Nlms algorithm is verified using simulations.
Non -negative constraints arise in certain system identification problems when the systems to be identified have only positive coefficients. This paper studies the stochastic behavior of modified lms and Nlms algorith...
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Non -negative constraints arise in certain system identification problems when the systems to be identified have only positive coefficients. This paper studies the stochastic behavior of modified lms and Nlms algorithms, modified so as to only allow adaptation with positive coefficients. The mean and second moment behavior of these algorithms are analyzed for Gaussian inputs. Excellent agreement is demonstrated between the theory and Monte Carlo simulations for the lms algorithm.
In this work it is presented a DSP card implementation method of the Fxlms single channel algorithm for active noise control (ANC). The ANC technique uses the superposition principle to attenuate acoustical noise. It ...
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ISBN:
(纸本)9781467393058
In this work it is presented a DSP card implementation method of the Fxlms single channel algorithm for active noise control (ANC). The ANC technique uses the superposition principle to attenuate acoustical noise. It is presented some simulating and experimental results of the lms and Fxlms algorithms. The signals used in the ANC are several low frequency tones and a broadband sound signal (air compressor), which is a machine widely used in industrial applications. The experiments are carried out in an enclosure (control room of approximately 36 cubic meters of volume).
There is a contradiction between convergence speed and steady-state error in the lms algorithm. When the step size factor is too large, the convergence speed is fast, but the error is larger. Otherwise, the reverse. I...
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There is a contradiction between convergence speed and steady-state error in the lms algorithm. When the step size factor is too large, the convergence speed is fast, but the error is larger. Otherwise, the reverse. In view of this contradiction, based on the original lms algorithm, consider from the correlation of the signal itself, has proposed a variable step size lms algorithm based on DCT transform. This algorithm combined with the original DCT-lms algorithm, through the introduction of Lorentzian function to achieve the change of step size factor, take full advantage of the relevant capacity of the DCT transform and Lorentzian function of the fast convergence ability. Simulation results show that the proposed algorithm has better convergence performance than the traditional adaptive filtering algorithm and DCT-lms algorithm, and has better steady state error.
Adaptive filtering in the frequency domain can be achieved by Fourier transformation of the input signal and independent weighting of the contents of each frequency bin. In certain applications, filtering in the frequ...
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Adaptive filtering in the frequency domain can be achieved by Fourier transformation of the input signal and independent weighting of the contents of each frequency bin. In certain applications, filtering in the frequency domain results in great improvements in convergence rate over the conventional time-domain adaptive filtering. In this paper, the use of word-level systolic arrays to implement frequency-domain adaptive filters based on the complex least mean square (I,MS) algorithm is described, The transform employed is the discrete Fourier transform (DFT). The proposed architecture operates on a block-by-block basis and makes use of the parallelism inherent in the computational problem under consideration. The input and output data flow sequentially and continuously into and out of the systolic arrays at the system clock rate. During each clock period, processing elements of three different types operate in parallel. The most computationally demanding among them performs only three consecutive multiplications and two addition/subtractions per clock period thereby allowing a very high throughput and very fast block signal processing to be achieved at the expense of a delay of 2L + 1 samples between the input and the output, L being the block size. (C) 1998 Elsevier Science Ltd. All rights reserved.
In order to solve the problem of lms algorithm, a new variable step-size lms algorithm is studied. The algorithm is based on the sigmoid function which builds the non-linear functional relationship between step and er...
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In order to solve the problem of lms algorithm, a new variable step-size lms algorithm is studied. The algorithm is based on the sigmoid function which builds the non-linear functional relationship between step and error. By introducing the error feedback strategy to adjust the parameters adaptively, the algorithm solves the problem of setting parameters in the function. Compared with other algorithms, simulation results show that the algorithm performs perfect at convergence rate and steady-state error with a better applicability.
This paper presents a new variable step size lms(Least-Mean-Square) adaptive filtering algorithm in adaptive echo cancellation. This step size algorithm builds a nonlinear function relationship between the step-size...
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This paper presents a new variable step size lms(Least-Mean-Square) adaptive filtering algorithm in adaptive echo cancellation. This step size algorithm builds a nonlinear function relationship between the step-size parameter and the error signal. Theoretical analysis and computer simulations show that convergence rate can be improved than the former by the proposed algorithm. The new algorithm has good performance. It is applied in the filtering process of adaptive echo cancellation. The filtering effect is good.
This paper examines the performance of an adaptive linear array employing the new Rlms algorithm, which consists of a recursive least square (RLS) section followed by a least mean square (lms) section. The performance...
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ISBN:
(纸本)9781424424238
This paper examines the performance of an adaptive linear array employing the new Rlms algorithm, which consists of a recursive least square (RLS) section followed by a least mean square (lms) section. The performance measures used are output and input signal-to-interference plus noise ratios (SINR), side lobe level (SLL), and Delta SINRo, as a function of the direction of arrival of the interfering signal. Computer simulation results show that the performance of Rlms is superior to either the RLS or lms based on these measures, particularly when operating with low input SINR.
In recent years, there is a growing effort in the learning algorithms area to propose new strategies to detect and exploit sparsity in the model parameters. In many situations, the sparsity is hidden in the relations ...
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ISBN:
(纸本)9781538646595
In recent years, there is a growing effort in the learning algorithms area to propose new strategies to detect and exploit sparsity in the model parameters. In many situations, the sparsity is hidden in the relations among these coefficients so that some suitable tools are required to reveal the potential sparsity. This work proposes a set of lms-type algorithms, collectively called Feature lms (F-lms) algorithms, setting forth a hidden feature of the unknown parameters, which ultimately would improve convergence speed and steady-state mean-squared error. The key idea is to apply linear transformations, by means of the so-called feature matrices, to reveal the sparsity hidden in the coefficient vector, followed by a sparsity-promoting penalty function to exploit such sparsity. Some F-lms algorithms for lowpass and highpass systems are also introduced by using simple feature matrices that require only trivial operations. Simulation results demonstrate that the proposed F-lms algorithms bring about several performance improvements whenever the hidden sparsity of the parameters is exposed.
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