Subband Beamforming of Miniature Microphone Arrays for Audio Applications*
Abstract
Microphone array processing techniques have generated a tremendous interest in both theoretical and applied areas, especially, over the past decade. So long as an array performs a type of spatial filtering, the dimension of array will determine the acceptable frequency-range of the incoming waves. Consequently, it is well known that, miniature microphone arrays are not appropriate for audio applications. In this paper, we introduce a novel technique to utilize miniature microphone arrays for detecting audio signals. Besides, the problem of low sensitivity of such arrays in low frequency beamforming, due to dealing with wideband audio signals, is resolved. We start our discussion with a Delayand-Sum beamformer, and extend it to the GSC-based beamformer, as an example of popular beamformers. Constant directivity is an important result of the proposed approach.
Keywords
Beamforming, microphone array, Filter banks, delay-and-sum beamformer, generalized sidelobe canceller
