ASA 128th Meeting - Austin, Texas - 1994 Nov 28 .. Dec 02

3pEA3. Wideband reverberation reduction in long-time acoustic signals produced by transducers in small test chambers.

Niels K. Winsor

Gary R. Hess

Forest E. White

Chris M. Young

Tetra Corp., 3701 Hawkins St. NE, Albuquerque, NM 87109-4512

Russ Roberts

Enigmatics, Inc., New Harmony, UT 84757-0537

For times long compared to the acoustic wave transit time in a test tank, the signal from point acoustic sources may be dominated by internal reflections and the modal response of the experimental tank in which experiments are performed. If the free-field source behavior of the acoustic source is desired, it can be extracted by taking advantage of special properties of the source/tank system. The transducer can be operated in a manner which permits characterization of the tank response; then the processed results can be used to reduce the effects of the tank response in the signals of interest. Spectral methods for this signal processing will be described and illustrated. The result is that signal characteristics in spectral regions of interest can be more clearly resolved and enhanced. [Work sponsored by U.S. Navy.]