Patent ID: 7848529

Claim:
A broadside small array microphone beamforming unit for adjusting a beam direction and reducing internal noise in a reference channel, comprising a first omni-directional microphone responding to input to generate a first signal X 1 ( t ); a second omni-directional microphone responding to input to generate a second signal X 2 ( t ); a first delay unit delaying the first signal X 1 ( t ) by a period T to generate a third signal X 1 ( t −T); a second delay unit delaying the second signal X 2 ( t ) by the period T to generate a fourth signal X 2 ( t −T); a first subtractor subtracting the third signal X 1 ( t −T) from the second signal X 2 ( t ) to generate a fifth signal R(t)=X 2 ( t )−X 1 ( t −T); a second subtractor subtracting the fourth signal X 2 ( t −T) from the first signal X 1 ( t ) to generate a sixth signal L(t)=X 1 ( t )−X 2 ( t −T); a third delay unit delaying the fifth signal R(t) by D samples to generate a seventh signal R′(t)=R(t−D); a gain function unit convoluting the sixth signal L(t) with a gain function G(t) to generate an eighth signal L′(t)=L(t)*G(t−i); a subtractor subtracting the eighth signal L′(t) from the seventh signal R′(t) to generate a ninth signal B′(t)=R′(t)−L′(t) an adder to add the first signal X 1 ( t ) and the second signal X 2 ( t ) to generate a tenth signal A(t)=X 1 ( t )+X 2 ( t ); a first voice activity detector VAD 1 detecting the correlation between the tenth signal A(t) and the ninth signal B′(t) to generate a correlated signal V 1 ( t ); a second voice activity detector VAD 2 detecting the non-correlation between the tenth signal A(t) and the ninth signal B′(t) to generate a non-correlated signal V 2 ( t ); a fourth delay unit delaying the ninth signal B′(t) by D 1 samples to generate an eleventh signal B′(t−D 1 ); a fifth delay unit delaying the ninth signal B′(t) by D 2 samples to generate a twelfth signal B′(t−D 2 ); a first adaptive filter suppressing correlated components and leaving non-correlated components between the tenth signal A(t) and the eleventh signal B′(t−D 1 ) to generate a thirteenth signal C(t) according to the correlated signal V 1 ( t ); and a second adaptive filter suppressing non-correlated components between the twelfth signal B′(t−D 2 ) and the thirteenth signal C(t) to generate a fourteenth signal B″(t) according to the non-correlated signal V 2 ( t ).