Acoustic beam former

Abstract

Abstract A beam former, including a receiving array which receives a sonar signal, which may be passive, and a receiver which processes the received signal. The receiving array includes a flat plate of material, capable of receiving reflected acoustic signals across its broad face, and an array of receiving elements, for example transducing elements disposed parallel to each other on the surface of the plate, the distance d between two adjacent elements being less than the velocity of propagation C of waves in the flat plate divided by the bandwidth B determied by the highest operating frequency of the array. Each element has a predetermined weight and polarity for its position in the array. A signal summer has as its inputs the outputs of each of the elements of the array. A cable is connected to the output of the signal summer. The beam former further comprises the receiver of the beam former, whose input is connected to the cable, comprising a plurality of transversal filters, each of whose inputs are connected to the cable, each filter having as may taps as there are elements in the array, the taps having the same weights and polarities, in the same order order or in reversed order, as the elements of the array, corresponding taps in the various transversal filters having different time delays with respect to adjacent taps in the same filter. The outputs of the filters thereby provide various compressions or expansions of the element weights, it thereby being possible to determine the direction of the incident signal by observing which filter has the largest output.

Inventors

• 👤 Harper John Whitehouse

Bibliographic Details