IPC분류정보
| 국가/구분 |
United States(US) Patent
등록
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| 국제특허분류(IPC7판) |
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| 출원번호 |
US-0449851
(1982-12-15)
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발명자
/ 주소 |
- Warnaka, Glenn E.
- Zalas, John M.
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| 출원인 / 주소 |
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| 대리인 / 주소 |
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| 인용정보 |
피인용 횟수 :
51 인용 특허 :
1 |
초록
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This invention is directed to a system for the active acoustic attenuation of noise produced in the interior of an enclosure by a source of noise which in one aspect comprises input sensing operable to sense the source noise to be attenuated, cancellor adapted to produce noise 180° out of phase with
This invention is directed to a system for the active acoustic attenuation of noise produced in the interior of an enclosure by a source of noise which in one aspect comprises input sensing operable to sense the source noise to be attenuated, cancellor adapted to produce noise 180° out of phase with the source noise and error sensor operable to sense the acoustic summation of the source noise and the noise produced by the cancellor. The input sensor, cancellor and error sensor are each preferably disposed at or immediately adjacent an area of high acoustic pressure within the enclosure. The system further includes a second input sensor disposed adjacent the source of noise, a second cancellor adapted to introduce noise 180° out of phase with the source noise at a location at or immediately adjacent the enclosure wall and second error sensor disposed in the interior of the enclosure. Each set of input sensing means, cancellor and error sensor are adapted to be connected to an electronic controller means operable to process signals from the input sensor, produce outputs to drive the cancellor for the introduction of cancelling sound waves into the enclosure for combination with the source sound waves, and then adjust such outputs based on signals received from the error sensor.
대표청구항
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1. A system for the attenuation of sound waves produced in a closed structure having walls, an exterior surface and an interior by a source of sound waves exterior to said closed structure, comprising: input sensing means disposed adjacent said exterior source of sound waves, said sensing means be
1. A system for the attenuation of sound waves produced in a closed structure having walls, an exterior surface and an interior by a source of sound waves exterior to said closed structure, comprising: input sensing means disposed adjacent said exterior source of sound waves, said sensing means being operable to produce electrical signals representing the amplitude and phase characteristics of said exterior sound waves, said exterior sound waves impinging against said exterior surface of said closed structure in a pattern and inducing vibration of said walls to produce sound waves in the interior of said body; cancelling means for generating cancelling sound waves of corresponding amplitude and 180° out-of-phase with said exterior sound waves; waveguide means disposed in the interior of said closed structure immediately adjacent said wall of said closed structure in the area of impingement of said exterior sound waves, and being spaced from said sensing means, said waveguide means being connected to said cancelling means to provide a path for the propagation of said cancelling sound waves to said closed structure wall for combination with said exterior sound waves; error sensing means disposed within said interior of said closed structure and being spaced from said waveguide means, said error sensing means being operable to produce electrical signals representing the amplitude and phase characteristics of said combination of said exterior sound waves and cancelling sound waves at said closed structure wall; and electronic controller means connected with said input sensing means, cancelling means and error sensing means, said electronic controller means being operable to process said electrical signals from said input sensing means, produce outputs for driving said cancelling means to produce said cancelling sound waves, and to adjust said outputs based on said electrical signals from said error sensing means for the production of revised outputs for driving said cancelling means. 2. The system of claim 1 wherein said waveguide means is formed with a section disposed from said enclosure wall a distance of approximately one wavelength of the highest frequency of said exterior sound waves to be attenuated. 3. The system of claim 1 wherein said waveguide means includes a section mounted immediately adjacent said enclosure wall, which section is formed in a shape approximating said pattern in which said exterior sound waves impinge against said exterior surface of said closed structure wall. 4. The system of claim 1 wherein separate sensing means, cancelling means, waveguide means and error sensing means are provided for each location of impingement of said exterior sound waves against said exterior surface of said closed structure. 5. A system for the attenuation of sound waves produced in a closed structure having walls, an interior and an exterior surface by at least one source of sound, said source sound waves producing a plurality of areas of high acoustic pressure and low pressure within said interior of said closed structure, and at least a portion of said source sound waves impinging against said exterior surface of said closed structure in a pattern and inducing vibration of said walls, said system comprising: first input sensing means disposed adjacent to an area of high acoustic pressure within said interior, and second input sensing means disposed adjacent said source of sound, said first and second input sensing means being operable to sense said source sound waves and produce electrical signals representing the amplitude and phase characteristics of said source sound sensed thereby; first cancelling means disposed within said closed structure and being spaced from said first input sensing means, and second cancelling means disposed adjacent said closed structure wall and being spaced from said second input sensing means, said first and second cancelling means being operable to generate cancelling sound waves of corresponding amplitude but 180° out-of-phase with said source sound waves for combination therewith; first error sensing means disposed adjacent to a high acoustic pressure area within said closed structure and being spaced from said first cancelling means, and second error sensing means disposed within said closed structure and being spaced from said second cancelling means, said first and second error sensing means being operable to sense the acoustic summation of said source sound waves and cancelling sound waves and produce electrical signals representing the amplitude and phase characteristics of said combination of said source sound waves and cancelling sound waves; and first electronic controller means connected with said first input sensing means, said first cancelling means and said first error sensing means, said first electronic controller means being operable to process said electrical signals from said first input sensing means, produce outputs for driving said first cancelling means to produce said cancelling sound waves, and to adjust said outputs based on said electrical signals from said first error sensing means for the production of revised outputs for driving said cancelling means; and second electronic controller means connected with said second input means, said second cancelling means and said second error sensing means, said second electronic controller means being operable to process said electrical signals from said second input sensing means, produce outputs for driving said second cancelling means to produce said cancelling sound waves, and to adjust said outputs based on said electrical signals from said second error sensing means for the production of revised outputs for driving said cancelling means. 6. The system of claim 5 wherein said second cancelling means includes at least one loudspeaker connected to a waveguide means, said waveguide means being disposed adjacent said closed structure wall. 7. The system of claim 6 wherein said waveguide means is formed with a section disposed from said enclosure wall a distance of approximately one wavelength of the highest frequency of said exterior sound waves to be attenuated. 8. The system of claim 6 wherein said waveguide means includes a section mounted immediately adjacent said enclosure wall, which section is formed in a shape approximating said pattern in which said exterior sound waves impinge against said exterior surface of said closed structure wall. 9. The system of claim 5 wherein separate sensing means, cancelling means, waveguide means and error sensing means are provided for each location of impingement of said exterior sound waves against said exterior surface of said closed structure.
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