An analog adaptive beamforming circuit for audio noise reduction

We have designed and built the first commercially available all-analog adaptive beamforming integrated circuit utilizing a dual microphone array. Beamforming performs spatial filtering by exploiting time-of-arrival differences between microphones. Our analog implementation has the advantage of using very little power which is important in portable, battery-powered devices. Rather than optimize parameters for a single filter as in a standard adaptive FIR filter used in conventional beamformers, our implementation selects among multiple filters each pre-programmed to provide various different spatial-filter patterns.