Microphone array sensor node for distributed wireless acoustic beamforming.

Abstract

The presentation will illustrate the use of field programmable gate arrays (FPGAs) in microphone array digital signal processing for wireless acoustic beamforming in source localization. We have developed a prototype of a node composed of ten microphone channels interfaced with a Xilinx-based FPGA board. The methodology involves basic signal conditioning and delay-and-sum beamforming programmed by VHDL. The prototype results illustrate significant increase in the sensitivity to acoustic sources in the direction of a signal, while rejecting noise from other directions. The sensitivity is also enhanced in relationship to the number of channels. This node prototype is a building block for a wireless sensor network, capable of distributed beamforming at about 10-kHz sample frequencies. Each node is designed to maximize throughput so that broadband acoustic sources are accommodated. We are now performing parametric studies to optimize the node design and microphone array geometry to provide maximum bandwidth, dynamic range, and adequate special resolution, while preserving the ability to resolve time delays between the microphones.