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Active acoustic noise cancellation with audio signal enhancement based on an almost-symmetrical time-varying autoregressive-moving average model

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JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 1996年第6期99卷 3528-3538页

作者： Tong, W Plotkin, EI Swamy, MNS Center for Signal Processing and Communications Department of Electrical and Computer Engineering Concordia University 1455 de Maisonneuve Boulevard West Montreal Quebec H3G 1M8 Canada

The basic idea of active noise cancellation (ANC)is to generate a controllable secondary source which compensates a noise in a certain spatial region. In headset applications, it is desirable to generate: a secondary source which cancels the acoustic noise field, while preserving the useful audio field. This requires that the cancellation algorithm possess an ability to differentiate between the useful audio signal and the cancellation residual at the secondary-sensor output. This is a formidable task for the conventional linear time-invariant filtering approach. since the Fourier spectra of acoustic noise and the audio signal occupy the same frequency bandwidth. In this paper, a two-sensor ANC scheme is presented with application to a noise-reduction headset. The active noise cancellation carried out is based on the concept of the separation of superimposed signals with complete overlapping spectra by using an almost-symmetrical time-varying autoregressive-moving average model (ASTV-ARMA), The significant advantages of our proposed selective noise cancellation approach are the cancellation of the undesirable noise field and the preservation of the useful audio wave field. Simulation results indicate that a noise reduction of over 30 dB can be achieved, thus resulting in a high-duality audio in the presence of a strong environmental acoustical noise. (C) 1996 Acoustical Society of America.

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Interference suppression in spread spectrum systems

Interference suppression in spread spectrum systems

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IEEE International Symposium on Spread Spectrum Techniques and Applications

作者： J.G. Proakis Department of Electrical and Computer Engineering Communications and Digital Signal Processing Center Northeastern University Boston MA USA

The interference immunity of a spread spectrum digital communication system corrupted by interference can be significantly enhanced by excising the interference prior to cross correlation of the received signal with the possible transmitted reference signals. In this paper we treat methods for excising narrowband (partial band) and broadband (impulsive) interference in direct-sequence and frequency-hopped spread spectrum systems. Excision methods based on linear prediction and nonlinear filtering algorithms are shown to be particularly effective for direct-sequence spread spectrum systems corrupted by narrowband interference. We also consider nonlinear excision methods for frequency-hopped spread spectrum systems corrupted by narrowband interference and direct-sequence spread spectrum systems corrupted by broadband (impulsive) interference.

关键词： Interference suppression Spread spectrum communication Narrowband Frequency Wideband Digital communication Jamming signal processing Degradation Matched filters

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Efficient simulation of cell loss probability in ATM networks with heterogeneous connection traffic descriptors

Efficient simulation of cell loss probability in ATM network...

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IEEE International Conference on communications (ICC)

作者： J.A. Freebersyser J.K. Townsend Center for Communications and Signal Processing Department of Electrical and Computer Engineering North Carolina State University Raleigh NC USA

In ATM networks, the purpose of connection admission control is to decide if allowing a new connection into the network violates a quality of service measure of the new connection or the existing connections. Instead of using statistical frame models, we represent the connection entering the network by the connection frame descriptors standardized by the ATM Forum and used by the connection admission control algorithms. We examine traffic sources described by heterogeneous connection frame descriptors in order to analyze constant bit rate sources versus variable bit rate sources, as well as different classes of variable bit rate sources. We use Monte Carlo simulation to estimate the cell loss probability of the combined traffic stream, as well as the individual classes using both random buffer filling and priority buffer filling schemes. Importance sampling is used to increase the efficiency of the simulation. For the experiments example considered, the improvement in simulation efficiency compared to conventional Monte Carlo simulation is inversely proportional to the estimate.

关键词： Intelligent networks Telecommunication traffic Traffic control Asynchronous transfer mode Communication system traffic control Quality of service Switches Monte Carlo methods Bit rate Admission control

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Performance comparisons of MSN codes for multi-track magnetic recording systems

Performance comparisons of MSN codes for multi-track magneti...

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IEEE Conference and Exhibition on Global Telecommunications (GLOBECOM)

作者： E. Kurtas J.G. Proakis M. Salehi Communications and Digital Signal Processing CDSP Center Department of Electrical and Computer Engineering Northeastern University Boston MA USA

We consider the coding for multi-track magnetic recording systems. We provide analytical results related to uncoded and coded multi-track systems which constitute the basis of the code construction. We have designed matched spectral null codes for multi-track recording systems which give coding gains from 3 dB to 4.8 dB over uncoded systems. We also provide the performance comparisons of such codes under various receiver (head) topologies.

关键词： Magnetic recording Modulation coding Magnetic modulators Interference constraints Timing Gain control Digital magnetic recording CD recording Digital signal processing Magnetic analysis

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Unsupervised model-based object recognition by parameter estimation of hierarchical mixtures

Unsupervised model-based object recognition by parameter est...

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IEEE International Conference on Image processing

作者： V. Kumar E.S. Manolakos Communications and Digital Signal Processing (CDSP) Center Electrical and Computer Engineering Department Northeastern University Boston MA USA

Model-based joint segmentation and recognition of objects is proposed in the framework of parameter estimation of hierarchical mixture densities. The maximum a posteriori (MAP) estimate of the parameters is computed by the application of a modified version of the expectation-maximization algorithm (EM with regularizing constraints applied to multiple level hierarchies). The approach is flexible in the sense that it allows for non-stationary pixel statistics, different noise models and is translation and scale invariant. Simulation results suggest that the scheme is well suited for recognition of partially occluded objects and recognition in complex and poorly modeled background.

关键词： Parameter estimation Image segmentation Labeling Application software signal processing algorithms Face detection Additive noise Parametric statistics Maximum likelihood estimation Digital signal processing

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Recent results on adaptive multiuser signal separation in CDMA;important steps in meeting the needs of third-generation wireless comm. systems

Recent results on adaptive multiuser signal separation in CD...

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IEEE International Conference on Personal Wireless Communication

作者： Y. Bar-Ness Center for Communications and Signal Processing Research Department of Electrical and Computer Engineering New Jersey Institute of Technology Newark NJ USA

CDMA is predicted to be an important method for the third generation wireless communication systems. However, for CDMA to satisfy the need for an increased number of simultaneous users, multiuser interference must be effectively combated. For such cancelers, adaptive methods are quite attractive. We summarize some of the results on adaptive multiuser detection, obtained at the center for Comm. and signal processing.

关键词： Source separation Multiaccess communication Detectors Multiple access interference Decorrelation Adaptive signal processing Code division multiplexing Time division multiple access Power control Interference elimination

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Comparative study of the linear minimum mean squared error (LMMSE) and the adaptive bootstrap multiuser detectors for CDMA communications

Comparative study of the linear minimum mean squared error (...

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IEEE International Conference on communications (ICC)

作者： H. Ge Y. Bar-Ness Department of Electrical & Computer Engineering Center of Communications and Signal Processing Research New Jersey Institute of Technology Newark NJ USA

We analyze the performance of linear minimum mean squared error (LMMSE) estimate-based multiuser detector for CDMA communication systems. Through numerical evaluation and computer simulations, we also compare the performance of the LMMSE detector and the adaptive bootstrap multiuser detector. Our analysis and simulations show that even though these two detectors were proposed based on different optimization criteria, they exhibit approximately equal performance in multiuser CDMA communications applications.

关键词： Detectors Multiaccess communication Performance analysis Adaptive signal processing computer simulation Interference suppression Filters Adaptive signal detection computer errors Computational modeling

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Selective reconstruction of objects from the Radon transform using the generalized instantaneous matched-filter approach

Selective reconstruction of objects from the Radon transform...

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IEEE International Conference on Electronics, Circuits and Systems (ICECS)

作者： R.R. Galigekere E.I. Plotkin Center for Signal Processing and Communications Department of Electrical & Comp Engineering Concordia University Montreal Canada

Selective reconstruction of objects of interest from a noisy Radon transform (a set of projections) of multiple objects is considered. The projections are separated by using a discrete, generalized version of the recently developed instantaneous matched filter (IMF). In this context, the IMF is reviewed from a discrete viewpoint. A generalized version that does not require an explicit orthogonalization, is described. The projections of the individual object of interest, separated by the generalized IMF, are used to reconstruct the corresponding object.

关键词： Image reconstruction Computed tomography Visualization Matched filters Biomedical imaging Density functional theory signal processing Discrete transforms Radar imaging Medical tests

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A distortion analysis and optimal design of orthogonal basis for DMT transceivers

A distortion analysis and optimal design of orthogonal basis...

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International Conference on Acoustics, Speech, and signal processing (ICASSP)

作者： Xueming Lin A.N. Akansu Department of Electrical and Computer Engineering Center for Communications and Signal Processing Research New Jersey Institute of Technology Newark NJ USA

An orthogonal transmultiplexer (synthesis/analysis filter bank) utilizing DFT (discrete fourier transform) basis is the current DMT (discrete multitone) standard for HDSL communications. The measures of the ICI and ISI distortions in a multicarrier modulation scheme are presented. The ICI and ISI performance of DFT along with other known linear transforms are compared. The issues of optimal basis design for a given channel are discussed. The available design tools of the subband transform theory are highlighted for the future performance improvements.

关键词： OFDM modulation Transceivers Filters Discrete transforms Frequency Intersymbol interference Amplitude modulation Discrete Fourier transforms Distortion measurement Interchannel interference

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Minimum mean square error design of stack filters

Minimum mean square error design of stack filters

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Midwest Symposium on Circuits and Systems (MWSCAS)

作者： C.E. Savin M.O. Ahmad M.N.S. Swamy Department of Electrical and Computer Engineering Centre for Signal Processing and Communications Concordia University Montreal QUE Canada

This paper addresses the problem of designing optimal stack filters under the most commonly used error criterion in filter design, namely, the minimum mean square error (MSE) between the desired signal and the estimated signal. It is shown that the MSE can be expressed as a linear combination of the responses of positive Boolean filters to different binary input vectors. As a result, a stack filter which is optimal for signal estimation in the MSE sense can be determined as the solution of a linear program.

关键词： Mean square error methods Nonlinear filters Estimation Filtering theory signal design Vectors Boolean functions Cost function signal processing computer errors

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