Title

Time-frequency representations for wideband acoustic signals in shallow water

Document Type

Conference Proceeding

Date of Original Version

12-1-2003

Abstract

Wideband acoustic propagation in shallow water has a unique arrival structure due to modal group speed dispersion. It is possible to unravel the modal dispersion characteristics using a proper time-frequency (TF) analysis. During the Asian Seas International Acoustics Experiment (ASIAEX) - East China Sea (ECS) experiment, signals collected by the vertical arrays have been processed using several time-frequency analysis techniques. Based upon the dispersion characteristics of acoustic propagation, theoretical time-frequency structure is used to determine the change of group delay. We present an improved time-frequency representation to provide higher resolution for TF diagrams using ECS data. The dispersion characteristics of ECS data are observed from these TF diagrams, and are verified by a theoretical model. Using this technique, higher modes can be observed with good resolution; this aids in increasing the performance of the inversion technique for long range sediment tomography.

Publication Title

Oceans Conference Record (IEEE)

Volume

5

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