Circular microphone array for meeting system

This paper describes two circular microphone arrays and a square microphone array which may be used for sound localization and sound capture. Sound capture by microphone array is achieved by Sum and Delay Beam Former (SDBF). A dedicated PCI 128-channel simultaneous input analog-to-digital (AD) board is developed for a 128-channel microphone array with a maximum sampling rate of 22.7 /spl mu/s/sample. Our 128-channel circular microphone array is under construction, but a 24 channel circular microphone array and a 128 channel square microphone array have been completed. The 24 channel circular microphone array can capture sound from an arbitrary direction. The 128-channel square microphone array can capture sound from a specific point. The 24-channel circular microphone array and the 128-channel square microphone array are evaluated by using frequency components of the sound. The 128-channel circular microphone array is evaluated by simulations of the sound pressure distribution. These microphone arrays will be used as the capture method of "a meeting system " which automatically takes minutes of a conference.