In this paper presents the comparison of the performance of the variable step-size lms adaptive algorithm and the fixed step-size lms adaptive algorithm for cancels multiple echoes signal in telephone networks. The co...
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ISBN:
(纸本)9788995003879
In this paper presents the comparison of the performance of the variable step-size lms adaptive algorithm and the fixed step-size lms adaptive algorithm for cancels multiple echoes signal in telephone networks. The core of this paper is a multiple delay estimator, which estimates and distributes delays to each individual fixed length short echo canceller. It is shown that the variable step-size lms adaptive algorithm yields the performances over the fixed step-size lms algorithm. Computer simulation results are provided to confirm the performances of the variable step-size lms algorithm.
This paper presents a method of improving the Transcranial Doppler (TCD) signal by removing harmonic interferences. Such interferences, originating from medical equipment using the high power HF signals are common in ...
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ISBN:
(纸本)081945415X
This paper presents a method of improving the Transcranial Doppler (TCD) signal by removing harmonic interferences. Such interferences, originating from medical equipment using the high power HF signals are common in a clinical environment, especially in the neighborhood of the operating theater. The Adaptive Interference Canceler based on the Nlms FIR filter has been used. The reference signal was obtained by delaying of the original TCD signal. The presented method allows significant improvement of a seriously disturbed TCD signal.
An adaptive filtering method is presented which eliminates ECG artifact from EMG signals based on error entropy criterion. In this method, the error distribution is estimated and minimized in an adaptive manner. Mean ...
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ISBN:
(纸本)9781538649169
An adaptive filtering method is presented which eliminates ECG artifact from EMG signals based on error entropy criterion. In this method, the error distribution is estimated and minimized in an adaptive manner. Mean squared error (MSE) criterion only minimizes 2nd order statistics of the error, so it is sufficient in cases where inherent noise is Gaussian. The error entropy (EE) criterion, used in the proposed algorithm, minimizes all moments of error distribution. So in EMG denoising, where ECG artifact is typically non -Gaussian, Minimum Error Entropy (MEE)- based adaptive algorithm will improve noise elimination performance. Simulation results show that proposed algorithm has better spectral coherence in low frequencies and improves the SNR of the denoised EMG signal (about 5dB), especially in low SNR inputs, compared to MSE based algorithms.
Global Positioning System (CPS) provides accurate, continuous, world-wide, three-dimensional position and velocity information to users with the appropriate receiving equipment. However, because GPS receiver relies on...
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ISBN:
(纸本)9781538665657
Global Positioning System (CPS) provides accurate, continuous, world-wide, three-dimensional position and velocity information to users with the appropriate receiving equipment. However, because GPS receiver relies on external radio frequency (RE) signals, they are vulnerable to unintentional interference or jamming. RF interference can result in degraded navigation accuracy or complete loss of receiver tracking. Thus, common GPS receivers equip with anti-jam algorithm to suppress the interference. In order to improve the anti-jam performance, it is meaningful and significant for us study how interference signal affects GPS receivers. In this paper, the interference performance of two single-tone interference against Least Mean Square (lms) algorithm in GPS receiver will be analyzed. Simulation results show that when there is specific frequency difference and specific angle difference between two single-tone interference under the condition of uniform linear array, the output Jam-to-Noise ratio (JNR) is bigger and single tone interference have good interference performance against lms algorithm in GPS receivers.
In the present work a novel approach for Active Noise Control (ANC) is attempted. A structural panel used as a secondary source for active noise control in a rectangular duct is developed and tested. The structural pa...
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ISBN:
(纸本)0819448680
In the present work a novel approach for Active Noise Control (ANC) is attempted. A structural panel used as a secondary source for active noise control in a rectangular duct is developed and tested. The structural panel is a square Aluminium trim panel, which is fixed on a steel frame vertically and excited by a electrodynamic exciter. The structural panel has many merits as an acoustic source over traditional loud speakers: it is simple in geometry, lower mass, easy in construction and requires only a simple modification of materials already installed on the duct. The vibration response and acoustic radiation response of the structural panel are studied for a simply supported boundary condition, when panel is subjected to less than 350 Hz harmonic excitation. Real time active noise control experiments are performed in a laboratory using the active structural panel as secondary source. Local attenuation of sound pressure levels of upto 45 dB is realized, in a particular location of the duct when its enclosure was excited by 210 Hz pure tone of harmonic sound.
This paper discusses two applications of adaptive filters for image processing on parallel architectures. The first, based on the results of previously accomplished work, summarizes the analyses of various adaptive fi...
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ISBN:
(纸本)0819418277
This paper discusses two applications of adaptive filters for image processing on parallel architectures. The first, based on the results of previously accomplished work, summarizes the analyses of various adaptive filters implemented for pixel-level image prediction. FIR filters, fixed and adaptive IIR filters, and various variable step size algorithms were compared with a focus on algorithm complexity against the ability to predict future pixel values. A gaussian smoothing operation with varying spatial and temporal constants were also applied for comparisons of random noise reductions. The second application is a suggestion to use memory-adaptive IIR filters for detecting and tracking motion within an image. Objects within an image are made of edges, or segments, with varying degrees of motion. An application has been previously published that describes FIR filters connecting pixels and using correlations to determine motion and direction. This implementation seems limited to detecting motion coinciding with FIR filter operation rate and the associated harmonics. Upgrading the FIR structures with adaptive IIR structures can eliminate these limitations. These and any other pixel-level adaptive filtering application require data memory for filter parameters and some basic computational capability. Tradeoffs have to be made between chip real estate and these desired features. System tradeoffs will also have to be made as to where it makes the most sense to do which level of processing. Although smart pixels may not be ready to implement adaptive filters, applications such as these should give the smart pixel designer some long range goals.
A new variable tap-length adaptive algorithm which exploits both second and fourth order statistics is proposed in this paper. In this algorithm, the tap-length of the adaptive filter is varying rather than fixed, and...
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ISBN:
(纸本)9781424421787
A new variable tap-length adaptive algorithm which exploits both second and fourth order statistics is proposed in this paper. In this algorithm, the tap-length of the adaptive filter is varying rather than fixed, and controlled by fourth order statistics, whereas the coefficient update retains a conventional least mean square (lms) form. As will be seen in the simulation results, the proposed algorithm has a faster convergence rate as compared with an existing variable tap-length lms algorithm which is based only on second order statistics in sub-Gaussian noise environments.
The methods to controlling the noise in a signal have attracted many researchers over past few years. One such approach is Adaptive Noise Cancellation which has been proposed to reduce steady state additive noise. Thi...
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ISBN:
(纸本)9781479939848
The methods to controlling the noise in a signal have attracted many researchers over past few years. One such approach is Adaptive Noise Cancellation which has been proposed to reduce steady state additive noise. This method uses two inputs - primary and reference. The primary input receives signal from the signal source which has been corrupted with a noise uncorrelated to the signal. The reference input receives noise signal uncorrelated with the signal but correlated in some way to the noise signal in primary input. The reference input is adaptively filtered to obtain a close estimate of primary input noise which is then subtracted from the corrupted signal at the primary input to produce an estimate of a clean uncorrupted signal, which is the Adaptive Noise Cancellation output. A desired signal corrupted by noise can be recovered by feeding back this output to Adaptive Filter and implementing Least Mean Square algorithm to minimize output power. The audio signal corrupted with noise is used as a primary input and a noise signal is used as reference input. Computer simulations are carried out using MA TLAB and experimental results are presented that illustrate the usefulness of Adaptive Noise Cancelling Technique.
Along with the increasing requests of the control level for power plant operation, accurate state parameters are needed for the advanced control, diagnosis and optimization algorithm. But the signal of the state param...
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ISBN:
(纸本)9781424447053
Along with the increasing requests of the control level for power plant operation, accurate state parameters are needed for the advanced control, diagnosis and optimization algorithm. But the signal of the state parameter is obscured by all kinds of noises in thermal system and difficult to analyze. To solve this problem, a novel least-mean-square(lms) algorithm is used for characteristic extracting in the adaptive noise cancellation (ANC) problem. An improved lms algorithm based on Sigmoid function was presented. The simulation result shows that a superior performance of the new algorithm in stationary environment and an equivalent performance in nonstationary environment. The experiment proves the method is effective and feasible for thermal processes signal analyzing.
Heart related problems are increasing day by day and heart signals are very important in the diagnosis of heart related problems. Many devices are added to these signals and are necessary to destroy these artifacts fr...
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ISBN:
(纸本)9781538608142
Heart related problems are increasing day by day and heart signals are very important in the diagnosis of heart related problems. Many devices are added to these signals and are necessary to destroy these artifacts from the original signal, so that the original signals are changing. Adaptive filters, as an effective cardiac signal filtering, require statistical characteristics of this signal method. This paper algorithm presents a new adaptive filter to remove artifacts from cardiac signals based on CSlms. Various methods of adaptive filters are proposed and finally found that adaptive filter based on the algorithm signal / noise ratio based on CSlms and mean class error is the best performance without increasing computational complexity.
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