SUBBAND FEEDBACK ACTIVE NOISE CANCELLATION
| Author: |
Siravara, Bharath M. |
| Advisor: |
Philip Loizou |
| URL: |
http://www.utdallas.edu/~loizou/thesis/bharath_ms_thesis.pdf
" target="_blank"> http://www.utdallas.edu/~loizou/thesis/bharath_ms_thesis.pdf
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| Completion Date: |
August 2002 |
| Degree: |
M.Sc./M.A. |
| Institution: |
University of Texas at Dallas |
| Abstract: |
This thesis presents a new technique for subband feedback active noise control. The problem of controlling the noise level in the environment has been the focus of a tremendous amount of research over the years. Active Noise Cancellation (ANC) is one such approach that has been proposed for reduction of steady state noise. ANC refers to an electromechanical or electroacoustic technique of canceling acoustic disturbance to yield a quieter environment. The basic principle of ANC is to introduce a canceling “antinoise” signal that has the same amplitude but the exact opposite phase, thus resulting in an attenuated residual noise signal. Wideband active noise control systems often involve adaptive filter lengths with hundreds of taps. Using subband processing can considerably reduce the length of the adaptive filter. Conventional subband algorithms are generally based in the frequency domain and use at least 2 sensors. This thesis presents a time domain algorithm for single sensor subband feedback ANC targeted for use in headsets and hearing protectors. The subband processing is done using relatively short fixed FIR filters. The algorithm also adopts the weight constrained NLMS algorithm for feedback ANC. Results showed that the proposed subband feedback ANC algorithm outperformed the traditional single band ANC system. |
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