Noise attenuation

• US 5,018,203 A
• Filed: 10/23/1989
• Issued: 05/21/1991
• Est. Priority Date: 02/24/1987
• Status: Expired due to Fees

• Current Assignee: Scientific Generics Limited (Science Group Plc)
• Original Assignee: Scientific Generics Limited (Science Group Plc)
• Inventors: Edge, Gordon M., Sawyers, Craig G.
• Primary Examiner(s): Isen, Forester W.
• Application Number:
  US07/399,451
• Time in Patent Office: 575 Days
• Field of Search: 381/96, 381/71, 381/59
• US Class Current: 381/71.2
• CPC Class Codes: A61F 11/145 electric, e.g. for active noise reduction
• CPC Class Codes: G10K 11/17857 Geometric disposition, e.g. placement of microphones
• CPC Class Codes: G10K 11/17875 using an error signal without a reference signal, e.g. pure feedback
• CPC Class Codes: G10K 11/17885 additionally using a desired external signal, e.g. pass-through audio such as music or speech
• CPC Class Codes: G10K 2210/1053 Hi-fi, i.e. anything involving music, radios or loudspeakers
• CPC Class Codes: G10K 2210/106 Boxes, i.e. active box covering a noise source; Enclosures
• CPC Class Codes: G10K 2210/108 Communication systems, e.g. where useful sound is kept and noise is cancelled
• CPC Class Codes: G10K 2210/1281 Aircraft, e.g. spacecraft, airplane or helicopter
• CPC Class Codes: G10K 2210/1291 Anti-Vibration-Control, e.g. reducing vibrations in panels or beams
• CPC Class Codes: G10K 2210/3011 Single acoustic input
• CPC Class Codes: G10K 2210/3217 Collocated sensor and cancelling actuator, e.g. "virtual earth" designs

Abstract

Apparatus for attenuating noise, particularly in an aircraft cabin, comprising a diaphragm (10) one side of which is subjected to the noise, sensing means (16) for sensing the displacement of the diaphragm in response to the noise, and deflecting means (20) responsive to the sensing means for deflecting the diaphragm in order to cancel the displacement, to attenuate noise transmitted from one side of the diaphragm to the other side of the diaphragm.

Claims

1. Apparatus for attenuating noise, the apparatus comprising a diaphragm one side of which is subjected to the noise, sensing means for sensing the actual displacement of the diaphragm in response to the noise, and deflecting means responsive to the sensing means for deflecting the diaphragm in order to cancel the displacement, to attenuate noise transmitted from one side of the diaphragm to the other side of the diaphragm, the diaphragm being divided up into separate areas, each area having a corresponding sensing means cooperating with a deflecting means, so that each area of the diaphragm is separately driven.

2. Apparatus according to claim 1, which is incorporated in headphones.

3. Apparatus according to claim 2 wherein said sensing means is an optical sensor.

4. Apparatus according to claim 3 wherein said sensing means comprises an interferometer.

5. Apparatus according to claim 1, in which the diaphragm is incorporated in a component of an aircraft cabin.

6. Apparatus according to claim 1 wherein said sensing means is an optical sensor.

7. Apparatus according to claim 6 wherein said sensing means comprises an interferometer.

8. Apparatus according to claim 5 wherein said sensing means is an optical sensor.

9. Apparatus according to claim 8 wherein said sensing means comprises an interferometer.

10. Apparatus for attenuating noise, the apparatus comprising a diaphragm one side of which is subjected to the noise, sensing means for sensing the actual displacement of the diaphragm in response to the noise, and deflecting means responsive to the sensing means for deflecting the diaphragm in order to cancel the displacement, to attenuate noise transmitted from one side of the diaphragm to the other side of the diaphragm, wherein the deflecting means are driven from the sensing means through a negative feedback loop which acts to null the displacement of the diaphragm, and wherein said apparatus is incorporated in headphones.

11. Apparatus according to claim 10 wherein said sensing means is an optical sensor.

12. Apparatus according to claim 11 wherein said sensing means comprises an interferometer.

13. Apparatus for attenuating noise, the apparatus comprising a diaphragm one side of which is subjected to the noise, sensing means for sensing the actual displacement of the diaphragm in response to the noise, and deflecting means responsive to the sensing means for deflecting the diaphragm in order to cancel the displacement, to attenuate noise transmitted from one side of the diaphragm to the other side of the diaphragm, wherein the deflecting means are driven from the sensing means through a negative feedback loop which acts to null the displacement of the diaphragm, and wherein the diaphragm is divided up into separate areas, each area having a corresponding sensing means cooperating with a deflecting means, so that each area of the diaphragm is separately driven.

14. Apparatus according to claim 13 wherein said sensing means is an optical sensor.

15. Apparatus according to claim 14 wherein said sensing means comprises an interferometer.

16. Apparatus for attenuating noise, the apparatus comprising a diaphragm one side of which is subjected to the noise, sensing means for sensing the actual displacement of the diaphragm in response to the noise, and deflecting means responsive to the sensing means for deflecting the diaphragm in order to cancel the displacement, to attenuate noise transmitted from one side of the diaphragm to the other side of the diaphragm, said apparatus being incorporated in headphones.

17. Apparatus according to claim 16 wherein said sensing means is an optical sensor.

18. Apparatus according to claim 17 wherein said sensing means comprises an interferometer.

19. Apparatus for attenuating noise, the apparatus comprising a diaphragm one side of which is subjected to the noise, sensing means for sensing the actual displacement of the diaphragm in response to the noise, and deflecting means responsive to the sensing means for deflecting the diaphragm in order to cancel the displacement, to attenuate noise transmitted from one side of the diaphragm to the other side of the diaphragm, wherein the deflecting means are driven from the sensing means through a negative feedback loop which acts to null the displacement of the diaphragm, the feedback loop includes an amplifier with an input to which an audio signal can be fed whereby the diaphragm will be deflected in accordance with the audio signal, and wherein the diaphragm is divided up into separate areas, each area having a corresponding sensing means cooperating with a deflecting means, so that each area of the diaphragm is separately driven.

20. Apparatus according to claim 19 wherein said sensing means is an optical sensor.

21. Apparatus according to claim 20 wherein said sensing means comprises an interferometer.

22. Apparatus for attenuating noise, the apparatus comprising a diaphragm one side of which is subjected to the noise, sensing means for sensing the actual displacement of the diaphragm in response to the noise, and deflecting means responsive to the sensing means for deflecting the diaphragm in order to cancel the displacement, to attenuate noise transmitted from one side of the diaphragm to the other side of the diaphragm, wherein the deflecting means are driven from the sensing means through a negative feedback loop which acts to null the displacement of the diaphragm, the feedback loop includes an amplifier with an input to which an audio signal can be fed whereby the diaphragm will be deflected in accordance with the audio signal, and wherein said apparatus is incorporated in headphones.

23. Apparatus according to claim 22 wherein said sensing means is an optical sensor.

24. Apparatus according to claim 23 wherein said sensing means comprises an interferometer.