1pSPc26. Chain architecture: An efficient hardware solution for a large microphone array system

A typical microphone array system consists of a number of microphones connected to the digitization hardware and central processing unit in a parallel fashion. Such radial, hub-and-spoke architecture has multiple points of failure, suffers from electromagnetic interference, and does not scale well. In this paper, an alternative, chain-like architecture is described. In such setup, the microphones in a system are organized in a single chain. Each individual microphone board has an ADC chip and is connected to the previous and to the next microphones in the chain with short multi-wire cables carrying digital signals. A buffer board at the end of the chain converts the digital data stream into the industry-standard USB 2.0 format. In this way, the individual microphone board becomes the building block for quick and easy arbitrary-configuration microphone array assembly with minimal amount of wiring involved. A hardware implementation of the chain architecture was developed and is described. Accompanying drivers and software allow the user to perform on-the-fly data acquisition and processing in C and in MATLAB. As an example, a 64-microphone array was built, and several source localization and beamforming algorithms were implemented in MATLAB. Experimental results using the data gathered from the array are presented.