Adaptive beamforming for noise reduction

An adaptive noise cancelling apparatus comprising:

• A. a receiving array including a plurality of spatially disposed sensors, each for receiving an input signal, comprising at least one of a component of target signal and a component of a noise signal, and for generating a signal representative of said input signal,
• B. primary signal means coupled with said receiving array for generating a primary signal representative of a first selected combination of one or more of said input-representative signals,
• C. reference signal means coupled with said receiving array for producing one or more signals representative of a second selected combination of said input-representative signals,
• D. adaptive filter means coupled to said reference signal means for generating a noise-approximating signal as a function of one or more noise component-representative signals produced during a selected period of time,
• E. output means coupled to said primary signal means and to said adaptive filter means for subtracting said noise-approximating signal from said primary signal to generate an output signal representative of said target signal,
• F. adaptation controlling means coupled with said receiving array for generating an SNR signal representative of a relative strength of said target signal to said noise signal,
• said adaptation controlling means including means coupled with said output means for generating an adaptation signal as a function of said output signal on said SNR signal, and
• G. modification means coupled with said adaptation controlling means and with said adaptive filter means for responding to said adaptation signal to selectively modify said noise-approximating signal to minimize a difference between it and one or more selected noise components of said primary signal.