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Riemann-Liouville operator-based fractional normalised least mean square algorithm with application to decision feedback equalisation of multipath channels

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IET SIGNAL PROCESSING 2016年第6期10卷 575-582页

作者： Shah, Syed Muslim Capital Univ Sci & Technol Dept Elect Engn Islamabad Pakistan

In this study, the authors modify the mapping function by introducing a non-linear term based on Riemann-Liouville definition of fractional derivatives and its application to the mean squared error in addition to the first-order partial derivatives;thus create fractional variants of the least mean square (lms) algorithm and its normalised version. The introduction of fractional term helps increase the convergence rate through the non-linear update term which depends on the fractional order and the in-process lms weights;for steep gradient of the error measure, large changes are made to the weights which help the equaliser filter to better track the effects of multipath fading channels. They verify and validate the working of the proposed technique in the decision feedback equalisation of multipath fading channels for higher-order quadrature amplitude modulations;comparative results are shown in terms of performance metrics as symbol-error rate for various fractional orders and step sizes, combined equaliser and channel responses for different number of training symbols;simulations show that the proposed approach outperforms the conventional counterpart.

关键词： multipath channels fading channels least mean squares methods decision feedback equalisers gradient methods filtering theory quadrature amplitude modulation error statistics Riemann-Liouville operator fractional normalised least mean square error algorithm decision feedback equalisation mapping function modification first-order partial derivative lms algorithm steep gradient equaliser filter multipath fading channel higher-order quadrature amplitude modulation symbol-error rate

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Design of Complex Non-Linear Adaptive Equalizer in Mitigating Severe Intersymbol Interferences

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JOURNAL OF SIGNAL PROCESSING SYSTEMS FOR SIGNAL IMAGE AND VIDEO TECHNOLOGY 2016年第2期84卷 225-236页

作者： Mandal, A. Mishra, R. Gautam Buddha Univ Sch Informat & Commun Technol Yamuna Expressway 201308 Greater Noida U India

In this paper, we propose an efficient architectural design for Adaptive Decision Feedback Equalizer (ADFE) for high-speed reliable data transmission through wired as well as wireless communication channels to minimize Inter Symbol Interference (ISI). High hardware cost of the system makes an urge to redesign it in order to minimize overall circuit complexity and cost. Realization of CORDIC based pipelined ADFE architecture using reformulated lms algorithm has not only reduced multipliers in its feed forward path, the flexibility and modularity of the components makes it possible for easy implementation also. The realization results area efficient, high speed and throughput with good convergence. The efficacy of the proposed equalizer is corroborated with MATLAB simulations for mitigation of severe channel distortion arise due to ISI in high speed communication systems.

关键词： Inter symbol interference Adaptive decision feedback equalizer CORDIC lms algorithm Pipelined multiplier

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Analog IC-achievable lineariser for power amplifiers based on adaptive feedforward

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ANALOG INTEGRATED CIRCUITS AND SIGNAL PROCESSING 2002年第3期33卷 231-238页

作者： Albertí, EB Sahad, AJZ Univ Politecn Cataluna Dept Signal Theory & Commun Barcelona 08034 Spain

A compensation technique for the amplitude and phase imbalances of a feedforward lineariser using the lms algorithm, implemented entirely in the analog domain, is presented. The lineariser is suited to RF power amplifiers, and maybe entirely developed with analog IC technologies. From simulated two-tone tests, the circuit leads to an intermodulation (IMD) reduction superior to 35 dB for a 64-QAM signal, being cheaper and competitive in performance with usual DSP-based adaptation circuits. Different implementations are evaluated, and the application of the circuit to RF power amplifiers in the DVB-T and in the LMDS frequency bands is considered.

关键词： feedforward lineariser power amplifiers lms algorithm analog signal processing analog integrated circuits

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Adaptive pose output decoupling for a hydraulically-driven 6-DOF parallel manipulator

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JOURNAL OF VIBRATION AND CONTROL 2011年第9期17卷 1417-1423页

作者： Yao Jianjun Fu Wei Hu Shenghai Harbin Engn Univ Coll Mech & Elect Engn Harbin Peoples R China

Since kinematic and dynamic coupling phenomena occur in a parallel manipulator, the outputs of the system corresponding to a sinusoidal pose contains coupling poses besides the fundamental input, causing coupling pose outputs. The method for pose output decoupling based on adaptive noise cancellation, a method for noise control and vibration control, is proposed here. The task is accomplished by generating a reference signal with the same frequency of the input pose. The reference input is weighted by the least mean square (lms) algorithm in such a way that it closely matches the coupling pose output. The weighted reference signal is added to the fundamental signal such that the coupling pose output is cancelled leaving the desired pose alone. The weights of the lms algorithm are adjusted by the coupling pose output, which is to be cancelled. The system is based on linkspace control, and its pose output is calculated in real-time from the actuator lengths by forward kinematics. The above concept is used as a basis for the development of an adaptive pose output decoupling algorithm. Experimental results performed with a hydraulically driven six degrees-of-freedom parallel manipulator demonstrate the efficiency and validity of the proposed control scheme.

关键词： 6-DOF parallel manipulator adaptive pose output decoupling coupling pose output lms algorithm

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A fast convergence algorithm for echo cancellers in full duplex transmission using back projection from slicer

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 2005年第4期53卷 1534-1549页

作者： Stopler, D Reuven, I Tel Aviv Univ Dept Elect Engn Syst IL-69978 Tel Aviv Israel

The problem of accelerating echo canceller tracking, during full duplex transmission, in single carrier (data) receivers with adaptive equalization is addressed. The scheme presented accelerates the convergence rate by orders of magnitude, with a minor increase in complexity, which can be traded for speed. The complexity may be reduced to a fraction of that of previously published acceleration schemes, while providing substantial speedup factors with respect to conventional echo cancellers. The new scheme is based on measuring the residual echo signal at the slicer (symbol-by-symbol detector) but applying the correction to the conventional echo canceller. Measuring changes in a low-noise (post-slicer) environment enables speedup of the adaptation. Updating the pre-equalizer echo canceller both reduces complexity and distills the echo from the noisy equalizer input.

关键词： adaptive digital filters convergence acceleration digital subscriber line DSL echo echo cancellation fast convergence fast echo canceller fast tracking lms algorithm

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Pipelining the adaptive decision feedback equalizer with zero latency

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SIGNAL PROCESSING 2003年第12期83卷 2675-2681页

作者： Chakraborty, M Pervin, S Indian Inst Technol Dept Elect & Elect Commun Engn Kharagpur 721302 W Bengal India

This paper extends a recently proposed approach to pipeline an adaptive filter to the case of least mean square (lms)-based adaptive decision feedback equalizer. It is shown that by certain manipulation of the equalizer weight update equation, a pipelined architecture can be realized which generates the output at the first stage itself and thus is free from any latency. The proposed method overcomes certain limitations of the conventional approaches in that due to the absence of any latency, there is no compulsion to employ delayed lms algorithm for coefficient adaptation and thus no compromise with convergence rate becomes necessary. (C) 2003 Elsevier B.V. All rights reserved.

关键词： latency decision feedback equalizer lms algorithm

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A Regularized Estimator For Linear Regression Model With Possibly Singular Covariance

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IEEE TRANSACTIONS ON AUTOMATIC CONTROL 2013年第1期58卷 236-241页

作者： Hong Son Hoang Baraille, Remy SHOM HOM F-31100 Toulouse France

A regularized estimator is proposed for regression models in the case where the covariances may be singular. Conditions guaranteeing proximity of a regularized estimator to the optimal estimator are obtained by appropriate choice of regularization parameters by allowing a prescribed level of uncertainty. A simple Monte-Carlo simulation study is reported to highlight some aspects and performance of the proposed approach.

关键词： Covariance matrix linear regression system lms algorithm parameter estimation regularization

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EEG adaptive noise cancellation using information theoretic approach

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BIO-MEDICAL MATERIALS AND ENGINEERING 2017年第4期28卷 325-338页

作者： Darroudi, Ali Parchami, Jaber Razavi, Morteza Kafaee Sarbisheie, Ghazaleh Sadjad Univ Technol Dept Elect Engn Jalal 64 StJalal Blvd Mashhad Iran Sadjad Univ Technol Dept Biomed Engn Mashhad Iran

OBJECTIVE: In this paper, an adaptive method based on error entropy criterion is presented in order to eliminate noise from Electroencephalogram (EEG) signals. METHOD: Conventionally, the Mean-Squared Error (MSE) criterion is the dominant criterion deployed in the adaptive filters for this purpose. By deploying MSE, only second-order moment of the error distribution is optimized, which is not adequate for the noisy EEG signal in which the contaminating noises are typically non-Gaussian. By minimizing error entropy, all moments of the error distribution are minimized;hence, using the Minimum Error Entropy (MEE) algorithm instead of MSE-based adaptive algorithms will improve the performance of noise elimination. RESULTS: Simulation results indicate that the proposed method has a better performance compared to conventional MSE-based algorithm in terms of signal to noise ratio and steady state error.

关键词： Adaptive filtering entropy lms algorithm MEE algorithm noise cancellation

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A New Mixed Variable Step Size Elms algorithm And Its Application in ANC

A New Mixed Variable Step Size ELMS Algorithm And Its Applic...

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2010 Second International Conference on E-Learning, E-Business, Enterprise Information Systems, and E-Government (EEEE 2010)

作者： Sun Li Jun School of Electrical Engineering Henan University of Technology Zhengzhou 450001, China ZHANG Shou_yong, WANG Xiang_li School of Information Science and Engineering Henan University of Technology Zhengzhou 450001, China

In this paper, we proposed a new mixed variable step size Elms algorithm (MVSS-Elms) which combined the mean square error and the correlation of the error to modify the step size. The approach is general in the sense that it not only retains the benefits of Elms algorithm lower steady-state error, but also improves the system convergence speed. In comparison, the new approach performance is much better than VSS-Elms algorithm and VFSS-Elms algorithm in the convergence speed and anti-noise capacity. Effectiveness of the proposed algorithm is demonstrated through computer simulations.

关键词： adaptive filtering noise canceller lms algorithm Elms algorithm

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Development and study of an automatic ac bridge for impedance measurement

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IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT 2001年第5期50卷 1048-1052页

作者： Dutta, M Rakshit, A Bhattacharyya, SN Jadavpur Univ Dept Elect Engn Kolkata 700032 W Bengal India

An automatic ac bridge method employing the principle of balancing by means of a stochastic gradient search algorithm is presented. Among the various gradient search techniques, the Widrow-Hoff least mean square (lms) technique has been chosen as it involves a low computational burden. The lms algorithm has been used by the authors for the operation of an ac bridge operating with continuous variables. The relevant operation has been verified by simulation;it can also measure negative impedance. A relation has been established between parameters to be used in the lms algorithm for discrete and continuous versions of the bridge. The balance convergence time for a relatively simple form of the lms bridge, namely, the R-R type bridge, has been theoretically established and experimentally verified both by simulation and real-time implementation. The frequency response of the lms algorithm has also been determined.

关键词： adaptive weight automatic ac bridge convergence factor lms algorithm negative impedance time varying impedance

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