The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 03, 1981
Filed:
Aug. 20, 1979
Jeffrey M Speiser, San Diego, CA (US);
The United States of America as represented by the Secretary of the Navy, Washington, DC (US);
Abstract
A frequency-domain beamformer is used with arrays comprising M rings with a maximum of N elements per ring, the positions of the elements having rotational symmetry. An element need not be present at each position. The outputs of each of the M rings of arrays are connected to the inputs of M sets of lowpass filters, each set comprising N filters. Each filter output is an input to a sample-and-hold circuit. A temporal discrete Fourier transform (DFT) is performed on the output signal from each sample-and-hold circuit. M demultiplexers, one for each of the M sets of DFT circuits, convert their parallel input signals into serial output signals. A memory, or function generator, is used for steering. A circular convolver convolves the outputs of the demultiplexers and the memories, the outputs of the convolvers being summed in an output summer. The beamformer is used with a 3-D array such that it has rotational symmetry, that is, if rotated at some angle, the situation is exactly the same as before the rotation.