Active high transmission loss panel

• US 5,315,661 A
• Filed: 08/12/1992
• Issued: 05/24/1994
• Est. Priority Date: 08/12/1992
• Status: Expired due to Term

• Current Assignee: Noise Cancellation Technologies, Inc. (NCT Group, Inc.)
• Original Assignee: Noise Cancellation Technologies, Inc. (NCT Group, Inc.)
• Inventors: Gossman, William, Eatwell, Graham
• Primary Examiner(s): Isen, Forester W.
• Application Number:
  US07/928,472
• Time in Patent Office: 650 Days
• Field of Search: 381/71, 381/94
• US Class Current: 381/71.1
• CPC Class Codes: G10K 11/1785 Methods, e.g. algorithms; Devices G10K11/1781, G10K11/1783 take precedence
• CPC Class Codes: G10K 11/17861 using additional means for damping sound, e.g. using sound absorbing panels
• CPC Class Codes: G10K 11/17873 using a reference signal without an error signal, e.g. pure feedforward
• CPC Class Codes: G10K 2210/118 Panels, e.g. active sound-absorption panels or noise barriers
• CPC Class Codes: G10K 2210/12 Rooms, e.g. ANC inside a room, office, concert hall or automobile cabin
• CPC Class Codes: G10K 2210/125 Transformers
• CPC Class Codes: G10K 2210/129 Vibration, e.g. instead of, or in addition to, acoustic noise
• CPC Class Codes: G10K 2210/1291 Anti-Vibration-Control, e.g. reducing vibrations in panels or beams
• CPC Class Codes: G10K 2210/3212 Actuator details, e.g. composition or microstructure
• CPC Class Codes: G10K 2210/3216 Cancellation means disposed in the vicinity of the source
• CPC Class Codes: G10K 2210/3217 Collocated sensor and cancelling actuator, e.g. "virtual earth" designs

Abstract

An active high transmission loss panel for quieting either one or two way sound radiation which incorporates a number of cells (11) which contain sensors and actuators (12) adapted to be controlled independently or interactively so as to attenuate noise attempting to pass through said panel.

Claims

1. An active high transmission loss panel for use in quieting broadband sound radiation, said panel comprising

panel means providing passive sound attenuation, said panel means including a plurality of first and second partition or partitioning means, with said panel means defining a number of contiguous cell means and being spaced from each other along the sound radiation path,

each first said partition means having a first sensor means thereon and each said corresponding second partition means having a first actuator and second sensor means thereon,

said actuator and sensor means, in conjunction with an active noise control means, adapted to attenuate noise impacting on said panel means from passing through to the opposite side.

2. A panel as in claim 1 wherein said first and second partition means, define, in conjunction with other partitions means, the said cell means and including

a second sensor means and second actuator means on said other partition means adapted to, in conjunction with a multi-input/multi-output controller means to attenuate noise transmission in two opposite directions.

3. A panel as in claim 1 wherein said cell means have a height and width which correspond to 1/4 to less than 1/3 of the wavelength of the highest frequency to be actively controlled.

4. A panel as in claim 3 wherein said cell means height and width are essentially equal.

5. A panel as in claim 3 wherein said cell means have a depth which is smaller than the height or width so that the wave propagation through the cell means is planar.

6. An active high transmission loss system for attenuating broadband noise radiation, said system comprising

a panel means providing passive sound attenuation,

said panel means consisting of a plurality of contiguous cell means,

sensor means located in each cell means,

actuator means located in each cell means,

said sensor means and actuator means being spaced one from the other is said cell means in the direction of noise radiation,

controller means operatively connected to said sensor and actuator means and adapted to attenuate noise impinging on said panel means.

7. A system as in claim 6 wherein said panel means includes

a first series of partition means, and

a second series of partition means,

said first and second series of partition means defining said cell means.

8. A system as in claim 7 wherein each cell means has multiple sensor and actuator means therein and said controller means is adapted to attenuate noise impinging on either side of the panel.

9. A system as in claim 6 wherein the cross-sectional dimensions of said cell means correspond to 1/4 to less than 1/3 of the wavelength of the highest frequency to be attenuated.

10. A system as in claim 9 wherein the depth of each cell means is smaller than the cross-sectional dimensions thereof so as to insure that the noise wave propagation through said cell means is planar.

11. An active high transmission loss panel for use in quieting broadband sound radiation, said panel comprising

panel means providing passive sound attenuation and comprising a multiplicity of first and second spaced partition means which define a corresponding number of contiguous cell means,

each said first partition means having a first sensor means thereon and each said corresponding second partition means having a first actuator means thereon and a second sensor means thereon, said first sensor means being spaced from said second sensor means,

said actuator and sensor means, in conjunction with an active noise control means, adapted to attenuate noise impacting on said panel means from passing through from one side to the opposite side.

12. An active high transmission loss panel as in claim 11 and including a second actuator means on said first partition means so as to allow attenuation of noise transmission in either direction through said panel.

13. A panel as in claim 11 and including an active noise controller means, said controller adapted to control each cell means actuator independently.

14. A panel as in claim 11 and including an active noise controller means, said controller means adapted to control said actuators in said cell means interactively.

15. A panel as in claim 11 the dimensions of said partition means is from one tenth to less than one third of the wavelength of the highest order mode being controlled.

16. A panel as in claim 11 wherein said cell means are hollows.

17. A panel as in claim 11 wherein said cell means are constructed of passive materials.