Beamformer with reduced sampling rate
First Claim
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1. A beamformer comprising:
- mixing means, said mixing means having terminals for receiving signals from the transducers of an array of transducers, said mixing means having terminals for receiving inphase and quadrature reference signals from a source of said inphase and quadrature reference signals, said mixing means mixing said transducer signals with said reference signals to translate said transducer signals to a lower frequency;
phase shifter means coupled to output terminals of said mixer means for applying phase shifts to individual ones of said transducer signals;
delay means coupled to individual ones of said phase shifters for imparting delays to individual ones of said transducer signals in accordance with the times of arrival of a wavefront of radiation upon said transducers of said array, said phase shifts of said phase shifting means being proportional to said delays of said delaying means; and
means coupled to said delaying means for summing said transducer signals to form a beam.
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Abstract
A beamformer for an array of sonar transducers, or electromagnetic radiating elements, includes mixers for translating the signals received by the transducers to a lower frequency. The beamformer incorporates delay lines operating at a clock rate which is reduced in proportion to the decrease in frequency. Each delay line provides delays to the signals of corresponding ones of the transducers in accordance with the time of arrival of a wavefront of radiation upon the respective transducers. Phase shifters coupled between the mixers and the delay lines impart phase shifts to the transducer signals proportional to the respective delays to compensate for the lowering of the frequency.
18 Citations
6 Claims
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1. A beamformer comprising:
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mixing means, said mixing means having terminals for receiving signals from the transducers of an array of transducers, said mixing means having terminals for receiving inphase and quadrature reference signals from a source of said inphase and quadrature reference signals, said mixing means mixing said transducer signals with said reference signals to translate said transducer signals to a lower frequency; phase shifter means coupled to output terminals of said mixer means for applying phase shifts to individual ones of said transducer signals; delay means coupled to individual ones of said phase shifters for imparting delays to individual ones of said transducer signals in accordance with the times of arrival of a wavefront of radiation upon said transducers of said array, said phase shifts of said phase shifting means being proportional to said delays of said delaying means; and means coupled to said delaying means for summing said transducer signals to form a beam. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification