Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 8 of 8 for “"Time-frequency distributions"”.
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Analysis of digital communication signals and extraction of parameters
… (BPSK), Quadrature Phase Shift Keying (QPSK), Frequency Shift Keying (FSK), and On-Off Keying (00K). The analysis emphasizes the use of available signal processing software. Detection methods compared include broadband energy detection, FFT- based narrowband energy detection, and two …
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Toward an interpretive framework of two-dimensional speech-signal processing
… representations of speech are derived from short-time segments of the signal and result in time-frequency distributions of energy such as the short-time Fourier transform and spectrogram. Speech-signal models of such representations have had utility in a variety of applications such as speech …
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Fusion of Frequency and Spatial Domain Information for Motion Analysis
… of multiple motions in video, which integrates frequency and spatial-domain information. The tasks of interest are finding the number of moving objects, velocity estimation, object tracking, and motion segmentation. The proposed hybrid approach performs the motion estimation based on …
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A Two -Dimensional Amplitude -Steered Array for Real -Time Volumetric Acoustic Imaging
Real-time volumetric ultrasound imaging is difficult due to problems with array construction and due to the slow speed of data collection. In 1976, a linear amplitude-steered array was introduced that uses reduced electronics to steer a monofrequency beam. The current study examines how the linear …
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Development of a Fourier Domain Low Coherence Interferometry Optical System for Applications in Early Cancer Detection
… shows that temporal coherence information in time frequency distributions contains valuable structural information about experimental samples. Additionally, the study of spatial coherence demonstrates the necessity of spatial resolution in white light interferometry systems. The coherence …
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Generating pictures from waves : aspects of image formation
… Fourier uncertainty principle by leveraging time-frequency distributions. We show that the number of sensors in a coherent imaging array defines a stable operating point relative to the phase noise. We introduce a digital phase tightening algorithm to reduce phase noise. We present a system …
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Acoustic Seabed and Target Classification using Fractional Fourier Transform and Time-Frequency Transform Techniques
… magnitude of the bottom impulse response. Joint time-frequency representations of the signal offer the possibility to determine the time-frequency configuration of the signal as its characteristic features for classification purposes. The classification is based on singular value decomposition of …
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Detection of Rotor and Load Faults in BLDC Motors Operating Under Stationary and Non-Stationary Conditions
Brushless Direct Current (BLDC) motors are one of the motor types rapidly gaining popularity. BLDC motors are being increasingly used in critical high performance industries such as appliances, automotive, aerospace, consumer, medical, industrial automation equipment and instrumentation. Fault …