This paper gives an analytical description of an adaptive microphone array
that facilitates a simple built-in calibration to the environment and instr
umentation. This method, suggested for use in hands-free mobile telephones
and speech recognition systems for cars, provides speech enhancement and ac
oustic echo-cancellation. The scheme offers several advantages, such as a s
imple calibration procedure, suppression of directional sources, versatile
robust beamforming, and reduced target signal distortion. The analysis empl
oys noncausal Wiener filters yielding compact and effective theoretical sup
pression limits.