Background Noise Reduction in Wind Tunnels using Adaptive Noise Cancellation and Cepstral Echo Removal Techniques for Microphone Array Applications

dc.contributor.authorSpalt, Taylor B.en
dc.contributor.committeechairFuller, Christopher R.en
dc.contributor.committeememberWicks, Alfred L.en
dc.contributor.committeememberBrooks, Thomas F.en
dc.contributor.departmentMechanical Engineeringen
dc.description.abstractTwo experiments were conducted to investigate Adaptive Noise Cancelling and Cepstrum echo removal post-processing techniques on acoustic data from a linear microphone array in an anechoic chamber. A point source speaker driven with white noise was used as the primary signal. The first experiment included a background speaker to provide interference noise at three different Signal-to-Noise Ratios to simulate noise propagating down a wind tunnel circuit. The second experiment contained only the primary source and the wedges were removed from the floor to simulate reflections found in a wind tunnel environment. The techniques were applicable to both signal microphone and array analysis. The Adaptive Noise Cancellation proved successful in its task of removing the background noise from the microphone signals at SNRs as low as -20 dB. The recovered signals were then used for array processing. A simulation reflection case was analyzed with the Cepstral technique. Accurate removal of the reflection effects was achieved in recovering both magnitude and phase of the direct signal. Experimental data resulted in Cepstral features that caused errors in phase accuracy. A simple phase correction procedure was proposed for this data, but in general it appears that the Cepstral technique is and would be not well suited for all experimental data.en
dc.description.degreeMaster of Scienceen
dc.publisherVirginia Techen
dc.rightsIn Copyrighten
dc.subjectWind Tunnelen
dc.subjectAdaptive Noise Cancellationen
dc.subjectConventional Beamformingen
dc.subjectLinear Arrayen
dc.subjectBackground Noise Reductionen
dc.subjectNoise Sourcesen
dc.titleBackground Noise Reduction in Wind Tunnels using Adaptive Noise Cancellation and Cepstral Echo Removal Techniques for Microphone Array Applicationsen
dc.typeThesisen Engineeringen Polytechnic Institute and State Universityen of Scienceen


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