Wideband-to-narrowband conversion method and apparatus
AssigneeThe United States of America as represented by the Secretary of the Navy
InventorsRobert J. McDonald, Joellen Wilbur
Life of this patent
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Abstract
A wideband-to-narrowband conversion method and apparatus performs the operational step of receiving an acoustic wideband signal, initially incident on an array of acoustic wideband transducers and subsequently digitized, and in response thereto generating a spatial Wigner bilinear kernel output signal, and the operational step of receiving and spatially bandpass filtering the spatial Wigner bilinear kernel output signal to remove a wideband low frequency portion as well as any unwanted noise therefrom and retain and output only a narrowband portion thereof.
Claims8
A wideband-to-narrowband conversion method, comprising the steps of:
- (a) receiving an acoustic wideband signal and, in response thereto, generating a spatial Wigner bilinear kernel output signal, said acoustic wideband signal being initially incident upon an array of linear acoustic transducers and outputted as an analog acoustic wideband signal by the array of linear acoustic transducers that is digitized before said generating of said spatial Wigner bilinear kernel output signal therefrom, said generating of the Wigner bilinear kernel output signal producing spatial Wigner bilinear kernel outputs for paired transducers of said transducer array symmetrically positioned relative to and in opposite directions from a center of said transducer array by multiplying the digitized outputs of said paired transducers with one another;
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- (b) receiving and spatially bandpass filtering said spatial Wigner bilinear kernel outputs to remove a wideband low frequency portion as well as any unwanted noise therefrom and retain and output only a narrowband portion thereof.
A wideband-to-narrowband conversion apparatus, comprising:
- (a) an array of linear acoustic transducers for receiving an acoustic wideband signal and outputting a sensed analog acoustic wideband signal;
- (b) an analog-to-digital convertor for receiving said sensed analog acoustic wideband signal and outputting a digitized acoustic wideband signal;
- (c) a Wigner bilinear kernel generator means for receiving said digitized acoustic wideband signal and, in response thereto, for generating spatial Wigner bilinear kernel outputs for paired transducers of said transducer array symmetrically positioned relative to and in opposite directions from a center of said transducer array by multiplying the digitized outputs of said paired transducers with one another;
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- (d) means for receiving and spatially bandpass filtering said spatial Wigner bilinear kernel outputs to remove a wideband low frequency portion as well as any unwanted noise therefrom and retain and output only a narrowband portion thereof.
Dependencies are inferred from the claim text.