Granted Patent B2

US 7,840,013 · App. 10/881,468 · Granted Nov 23, 2010

Abstract

Claims (8)

1. A sensor array for use in a beamformer, comprising: a diffracting structure having a radius (a) greater than 2/k in at least one plane of interest, where k is 2πf/c, λ=c/f and c is the speed of sound, λ is the wavelength of sound and f is the lowest frequency of interest;

at least two cavities in the perimeter of said diffracting structure; and

at least two sensors disposed at the ends of respective ones of said cavities and spaced apart by more than λ/2, wherein said beamformer reverts to a single one of said sensors above a predetermined frequency (f) that is greater than the lowest frequency of interest.

2. The sensor array of claim 1 , wherein said cavities are shaped as truncated cones.

3. The sensor array of claim 1 , wherein said cavities are sectoral shaped.

4. The sensor array of claim 1 , wherein said cavities are V shaped.

5. The sensor array of claim 1 , wherein said sensors are omnidirectional microphones.

6. The sensor array of claim 1 , further including acoustically absorptive materials applied to the surface of said diffracting object to provide acoustic impedance for increased directivity above said predetermined frequency.

Assignments (32)