3aSPa7. Adaptive noise cancellation with directional microphones.

Session: Wednesday Morning, December 4

Time: 10:15

Abstract:

The use of adaptive noise cancellation in communication devices has now been under investigation for more than two decades. Early studies predicted large SNR gains that were rarely obtained when actual devices were tested in typical acoustic noise environments. One of the problems encountered was the lack of coherence between the ``noise'' sensor and the actual corrupting noise signal. The measured low coherence values were most probably due to time-varying multipath, multiple uncorrelated noise sources, and nonlinearities in the signal and noise transmission paths. This talk will address the expected noise cancellation that can be obtained by using directional microphones to spatially filter the acoustic field into signal-plus-noise and noise channels. Analytical results for spherically and cylindrically isotropic noise fields will be shown and discussed.