Current Search: Acoustic filters (x)
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Title
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Digital acoustic communications using decision directed learning.
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Creator
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Alleyne, Jochen Raoul, Florida Atlantic University, LeBlanc, Lester R., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
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Abstract/Description
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This document serves as a dissertation for the Doctor of Philosophy in Ocean Engineering degree at Florida Atlantic University's Department of Ocean Engineering. This dissertation documents the design, development, and performance analysis of an acoustic receiver system that incorporates a decision directed learning filter for acoustic multi-phase shift keying signals. The system makes use of advanced signal processing, inclusive of spatial diversity and decision directed learning techniques...
Show moreThis document serves as a dissertation for the Doctor of Philosophy in Ocean Engineering degree at Florida Atlantic University's Department of Ocean Engineering. This dissertation documents the design, development, and performance analysis of an acoustic receiver system that incorporates a decision directed learning filter for acoustic multi-phase shift keying signals. The system makes use of advanced signal processing, inclusive of spatial diversity and decision directed learning techniques in order to decode digital acoustic data. Error correcting techniques are also employed as well as methods of analyzing the efficiency of the system.
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Date Issued
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2001
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PURL
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http://purl.flvc.org/fcla/dt/11951
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Subject Headings
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Underwater acoustic telemetry, Digital communications, Acoustic filters
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Format
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Document (PDF)
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Title
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Source speed estimation using a pilot tone in a high-frequency acoustic modem.
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Creator
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Kathiroli, Poorani., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
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Abstract/Description
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This thesis proposes to estimate the speed of a moving acoustic source by either linear or non linear processing of the resulting Doppler shift present in a high-frequency pilot tone. The source is an acoustic modem (Hermes) which currently uses moving average to estimate and compensate for Doppler shift. A new auto regressive approach to Doppler estimation (labeled IIR method in the text) promises to give a better estimate. The results for a simulated peak velocity of 2 m/s in the presence...
Show moreThis thesis proposes to estimate the speed of a moving acoustic source by either linear or non linear processing of the resulting Doppler shift present in a high-frequency pilot tone. The source is an acoustic modem (Hermes) which currently uses moving average to estimate and compensate for Doppler shift. A new auto regressive approach to Doppler estimation (labeled IIR method in the text) promises to give a better estimate. The results for a simulated peak velocity of 2 m/s in the presence of additive noise showed an RMSE of 0.23 m/s using moving average vs. 0.00018 m/s for the auto regressive approach. The SNR was 75 dB. The next objective was to compare the estimated Doppler velocity obtained using the two algorithms with the experimental values recorded in real time. The setup consisted of a receiver hydrophone attached to a towing carriage that moved with a known velocity with respect to a stationary acoustic source. The source transmitted 375 kHz pilot tone. The received pilot tone data were preprocessed using the two algorithms to estimate both Doppler shift and Doppler velocity. The accuracy of the algorithms was compared against the true velocity values of the carriage. The RMSE for a message from experiments conducted indoor for constant velocity of 0.4 m/s was 0.6055 m/s using moving average, 0.0780 m/s using auto regressive approach. The SNIR was 6.3 dB.
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Date Issued
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2011
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PURL
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http://purl.flvc.org/FAU/3171396
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Subject Headings
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Underwater acoustics, Measurement, SIgnal processing, Digital techniques, Digital filters (Mathematics), Radio frequency, Mathematical models
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Format
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Document (PDF)
