Theses and Dissertations
Now showing items 1-10 of 18
Clock Synchronization Through Time-Variant Underwater Acoustic Channels
(Monterey, California. Naval Postgraduate School, 2012-09)
The goal of this work is to develop methodologies for synchronizing the clocks of neighboring nodes of an underwater acoustic network. Clock synchronization requires an estimate of the signaling time delay between the ...
Direct-sequence spread-spectrum acoustic communications with CRV Decomposition
(Monterey, California. Naval Postgraduate School, 2004-06)
Direct-Sequence Spread-Spectrum (DS-SS) is among the preferred modulation techniques for military applications. DS-SS offers three greatly desired characteristics. It allows for the development of Low Probability of Detection ...
Performance of acoustic spread-spectrum signaling in simulated ocean channels
(Monterey, California. Naval Postgraduate School, 2003-06)
Direct-Sequence Spread Spectrum (DSSS) modulation is being advanced as the physical-layer basis for Seaweb undersea acoustic networking. DSSS meets the need for channel tolerance, transmission security, and multi-user ...
Acoustic transient TDOA estimation and discrimination
(Monterey, California. Naval Postgraduate School, 2000-09)
This thesis examines acoustic transient discrimination and Time Difference Of Arrival (TDOA) estimation for the purposes of estimating the position of a submarine in a sonobuoy field. Transient discrimination, for this ...
An analysis of the IIR an FIR Wiener filters with applications to underwater acoustics
(Monterey, California. Naval Postgraduate School, 1997-06)
A detailed analysis of the performance the Wiener optimal filter for estimating a signal in additive noise is carried out. A first order AR model is assumed for both the signal and noise. Both IIR and FIR forms of the ...
Denoising of ocean acoustic signals using wavelet-based techniques
(Monterey, California. Naval Postgraduate School, 1996-12)
This thesis investigates the use of wavelets, wavelet packets and cosine packet signal decompositions for the removal of noise from underwater acoustic signals. Several wavelet based denoising techniques are presented and ...
Detection and identification of cyclostationary signals
(Monterey, California. Naval Postgraduate School, 1996-03)
Propeller noise can be modeled as an amplitude modulated (AM) signal. Cyclic Spectral Analysis has been used successfully to detect the presence of analog and digitally modulated signals in communication systems. It can ...
Shallow water reverberation measurement and prediction
(Monterey, California. Naval Postgraduate School, 1994-06)
Low frequency active sonar performance in shallow water is often limited by reverberation. Reverberation modeling in shallow water has been difficult due to the complexity of the multipath acoustic propagation problem ...
Signal processing for the 1992 barents sea tomography experiment
(Monterey, California. Naval Postgraduate School, 1993-12)
In August 1992, an acoustic tomography experiment was conducted in the Barents Sea. The objective of this thesis is the development of space-time signal processing algorithms to extract the arrival times of rays and modes ...
Numerical modeling of a free-flooded piezoelectric ring sonar transducer.
(Monterey, California. Naval Postgraduate School, 1993-03)
A two-dimensional finite element model of a low frequency, free- flooded piezoelectric thin ring sonar transducer was developed for use with the ATILA code. Effective material properties for the ring were determined from ...
Branch Of Service
Electrical Engineering (18)
Engineering Acoustics (18)