Browsing George R. Brown School of Engineering by Author "Jones, Douglas L."
Now showing items 1-33 of 33
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An Adaptive Optimal-Kernel Time-Frequency Representation
(1995-10-01)Time-frequency representations with fixed windows or kernels figure prominently in many applications, but perform well only for limited classes of signals. Representations with signal- dependent kernels can overcome this ... -
Applications of Adaptive Time Frequency Representations to Underwater Acoustic Signal Processing
(1991-11-01)The authors describe the application of an adaptive optimal kernel (AOK) time-frequency representation to the processing of underwater acoustic data. The optimal kernel is a signal-dependent radially Gaussian function. ... -
Blind Quadratic and Time Frequency Based Detectors from Training Data
(1995-01-20)Time-frequency based methods, particularly quadratic (Cohen's-class) representations, are often considered for detection in applications ranging from sonar to machine monitoring. We propose a method of obtaining near-optimal ... -
A Canonical Covariance Based Method for Generalized Joint Signal Representations
(1996-04-20)Generalized joint signal representations extend the scope of joint time-frequency representations to a richer class of nonstationary signals. Cohen's marginal-based generalized approach is canonical from a distributional ... -
Community Driven Digital Signal Processing Laboratories in Connexions
(2004-06-01)The conventional textbook is largely inadequate for digital signal processing (DSP) laboratory education due to inherent factors such as a small and fragmented market and rapid hardware obsolescence. Freely available ... -
Design of Training Data Based Quadratic Detectors with Application to Mechanical Systems
(1996-01-20)Reliable detection of engine knock is an important issue in the design and maintenance of high performance internal combustion engines. Cost considerations dictate the use of vibration signals, measured at the engine ... -
Efficient Approximation of Continuous Wavelet Transforms
(1991-04-01)An efficient method, based on the chirp-z transform, for computing equally spaced time samples of a continuous wavelet transform at arbitrary scale samples is developed. Applications include efficient computation of samples ... -
Equivalence of Generalized Joint Signal Representations of Arbitrary Variables
(1996-12-20)Joint signal representations (JSRs) of arbitrary variables generalize time-frequency representations (TFRs) to a much broader class of nonstationary signal characteristics. Two main distributional approaches to JSRs of ... -
Generalized Joint Signal Representations and Optimum Detection
(1996-01-20)Generalized joint signal representations (JSRs) extend the scope of joint time-frequency representations (TFRs) to a richer class of nonstationary signals, but their use, just as in the case of TFRs, has been primarily ... -
Improved Time-Frequency Filtering of Signal-Averaged Electrocardiograms
(1995-01-15)A recently proposed time-frequency filtering technique has shown promising results for the enhancement of signal-averaged electrocardiograms. This method weights the short-time Fourier transform (STFT) of the ensemble-averaged ... -
Integral Transforms Covariant to Unitary Operators and their Implications for Joint Signal Representations
(1996-06-01)Fundamental to the theory of joint signal representations is the idea of associating a variable, such as time or frequency, with an operator, a concept borrowed from quantum mechanics. Each variable can be associated ... -
Multilingual Open-Content Signal Processing Laboratories in Connexions
(2004-11-01)Due to inherent factors like a small and fragmented market and rapid hardware obsolescence, the conventional textbook is inadequate for DSP laboratory education. Freely available open-content materials that enable and ... -
New Dimensions In Wavelet Analysis
(1992-03-01)In this paper we propose a new class of signal analysis tools that generalizes the popular wavelet and short-time Fourier transforms. The class allows skews and rotations of the analyzing wavelet in the time-frequency ... -
New Signal-Space Orthonormal Bases via the Metaplectic Transform
(1992-10-01)The discretization of the metaplectic transform (MT) is considered, and it is shown that it can lead to completely new orthonormal bases (ONBs) for the signal space of square integrable functions. Two new classes of bases, ... -
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Optimal Detection Using Bilinear Time Frequency and Time Scale Representations
(1995-12-20)Bilinear time-frequency representations (TFRs) and time-scale representations (TSRs) are potentially very useful for detecting a nonstationary signal in the presence of nonstationary noise or interference. As quadratic ... -
Optimal Kernels for Nonstationary Spectral Estimation
(1995-02-20)Current theories of a time-varying spectrum of a nonstationary process all involve, either by definition or by difficulties in estimation, an assumption that the signal statistics vary slowly over time. This restrictive ... -
Optimal Reduced Rank Time-Frequency/Time Scale Quadratic Detectors
(1996-01-20)Optimal detectors based on time-frequency/time-scale representations (TFRs/TSRs) admit a representation in terms of a bank of spectrograms/scalograms that yields a large class of detectors. These range from the conventional ... -
Optimum Quadratic Detection and Estimation Using Generalized Joint Signal Representations
(1996-12-01)Time-frequency analysis has recently undergone significant advances in two main directions: statistically optimized methods that extend the scope of time-frequency-based techniques from merely exploratory data analysis to ... -
A Radially-Gaussian, Signal-Dependent Time-Frequency Representation
(1991-04-01)An optimization formulation for designing signal-dependent kernels that are based on radially Gaussian functions is presented. The method is based on optimality criteria and is not ad hoc. The procedure is automatic. The ... -
Sharing Knowledge and Building Communities in Signal Processing
(2004-09-01)The textbook has traditionally been the fundamental tool of university teaching. The text both serves as the repository of facts and information and provides the recommended structure and sequence for teaching and learning ... -
Shear Madness: New Orthonormal Bases and Frames Using Chirp Functions
(1993-12-01)The proportional-bandwidth and constant-bandwidth time-frequency signal decompositions of the wavelet, Gabor, and Wilson orthonormal bases have attracted substantial interest for representing nonstationary signals. However, ... -
A Signal Dependent Time Frequency Representation: Optimal Kernel Design
(1993-04-01)Time-frequency distributions (TFDs), which indicate the energy content of a signal as a function of both time and frequency, are powerful tools for time-varying signal analysis. The lack of a single distribution that is ... -
Signal-Dependent Time-Frequency Analysis using a Radially Gaussian Kernel
(Elsevier, 1993-01-15)Time-frequency distributions are two-dimensional functions that indicate the time-varying frequency content of one-dimensional signals. Each bilinear time-frequency distribution corresponds to a kernel function that ... -
A Signal-Dependent Time-Frequency Representation: Fast Algorithm for Optimal Kernel Design
(1994-01-01)A time-frequency representation based on an optimal, signal-dependent kernel has been proposed recetnly in an attempte to overcome one of the primary limitations of bilinear time-frequency distributions: that the best ... -
A Simple Covariance Based Characterization of Joint Signal Representations of Arbitrary Variables
(1996-01-20)Joint signal representations of arbitrary variables extend the scope of joint time-frequency representations, and provide a useful description for a wide variety of nonstationary signal characteristics. Cohen's marginal-based ... -
A Simple Scheme for Adapting Time-Frequency Representations
(1994-12-01)Signal-dependent time-frequency representations, by adapting their functional form to fit the signal being analyzed, offer many performance advantages over conventional representations. In this paper, we propose a simple, ... -
A Simple Scheme for Adapting Time-Frequency Representations
(1992-10-01)Current signal-dependent time-frequency representations are block-oriented methods suited only for short-duration signals. The authors propose a simple, computationally efficient technique for creating adaptive time-frequency ... -
Time Frequency Detectors
(1996-01-20)Time-frequency representations (TFRs) provide a powerful and flexible structure for designing optimal detectors in a variety of nonstationary scenarios. In this paper, we describe a TFR-based framework for optimal detection ... -
Unitary Equivalence and Signal Processing
(1993-08-01)The notions of time, frequency, and scale are generalized using concepts from unitary operator theory and eigenanalysis. The result is an infinite number of new signal analysis and processing tools that are implemented ... -
Unitary Equivalence: A New Twist on Signal Processing
(1995-10-01)Unitary similarity transformations furnish a powerful vehicle for generating infinite generic classes of signal analysis and processing tools based on concepts different from time, frequency, and scale. Implementation of ... -
Warped Wavelet Bases: Unitary Equivalence and Signal Processing
(1993-04-01)The notions of time, frequency, and scale are generalized using concepts from unitary operator theory and applied to time-frequency analysis, in particular the wavelet and short-time Fourier transform orthonormal bases and ... -
Wigner-Based Formulation of the Chirplet Transform
(1996-12-01)Using the Wigner distribution, we derive and analyze a matrix formulation for the chirplet transform, a signal analysis tool that generalizes the wavelet and short-time Fourier transforms. The formulation expresses the ...
