Noise cancellation methodology for electronic devices

• US 20050254664A1
• Filed: 05/13/2004
• Published: 11/17/2005
• Est. Priority Date: 05/13/2004
• Status: Abandoned Application

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Kwong, Wah Yiu, Wong, Hong W.
• Application Number:
  US10/845,676
• Publication Number:
  US 20050254664A1
• Time in Patent Office: Days
• US Class Current: 381/71.200
• CPC Class Codes: G10K 11/17821 characterised by the analysis of the input signals only
• CPC Class Codes: G10K 11/17823 Reference signals, e.g. ambient acoustic environment
• CPC Class Codes: G10K 11/1783 handling or detecting of non-standard events or conditions, e.g. changing operating modes under specific operating conditions
• CPC Class Codes: G10K 11/17835 using detection of abnormal input signals
• CPC Class Codes: G10K 11/17837 by retaining part of the ambient acoustic environment, e.g. speech or alarm signals that the user needs to hear
• CPC Class Codes: G10K 11/17857 Geometric disposition, e.g. placement of microphones
• CPC Class Codes: G10K 11/17873 using a reference signal without an error signal, e.g. pure feedforward
• CPC Class Codes: G10K 11/17875 using an error signal without a reference signal, e.g. pure feedback
• CPC Class Codes: G10K 2210/12 Rooms, e.g. ANC inside a room, office, concert hall or automobile cabin

Abstract

A system for generating a noise cancellation waveform is described. Specifically, the system captures a noise waveform, executes a noise cancellation algorithm, and communicates the noise cancellation waveform to a working environment. The noise cancellation algorithm comprises a delay parameter, a reflective index, and distortion variables.

Claims

1. A method, comprising:

capturing a first waveform from a working environment with a microphone;

generating a second waveform to cancel the first waveform;

adjusting the second waveform based on a delay parameter that accounts for the distance between a user and the microphone; and

communicating the second waveform through a speaker.

2. The method of claim 1, further comprising:

monitoring and adjusting the gain of the second waveform communicated through the speaker, wherein the gain is clipped at a predetermined level.

3. The method of claim 1, further comprising:

selecting a reflective index based on features of the working environment, wherein the reflective index is a factor in generating the second waveform.

4. The method of claim 3, wherein the reflective index is obtained via a lookup table.

5. The method of claim 1, further comprising:

calculating a distortion variable, wherein the distortion variable is used to adjust the second waveform.

6. A computer system, comprising:

a processor;

a transmit audio circuitry coupled to the processor to amplify a noise cancellation signal;

a speaker coupled to the transmit audio circuitry to transmit the noise signal cancellation signal, wherein the speaker is mounted to a display facing away from a user of the computer system; and

a user interface coupled to the processor, wherein the user interface allows the user of the computer system to adjust variables used to generate the noise cancellation signal.

7. The computer system of claim 6, further comprising:

a memory coupled to the processor, wherein the memory comprises an algorithm to generate the noise cancellation signal.

8. The computer system of claim 6, further comprising:

a microphone coupled to the processor, wherein the microphone samples ambient noise.

9. The computer system of claim 8, further comprising:

a receive audio circuitry to the microphone, wherein the receive audio circuitry converts an analog signal to a digital signal.

10. The computer system of claim 6, wherein the transmit audio circuitry converts a digital signal to an analog signal.

11. The computer system of claim 6, wherein the computer system is a mobile computer system.

12. The computer system of claim 6, wherein the computer system is a desktop computer system.

13. An electronic device, comprising:

means for compensating for a delay in transmitting a noise cancellation signal to a user;

means for setting a reflective index; and

means for calibrating a signal distortion.

14. The electronic device of claim 13, further comprising:

means for capturing noise.

15. The electronic device of claim 13, further comprising:

means for communicating the noise cancellation signal.

16. The electronic device of claim 13, further comprising:

means for adjusting a frequency filter.

17. The electronic device of claim 13, further comprising:

means for limiting the gain of the noise cancellation signal.

18. An article comprising a machine readable medium having a plurality of machine readable instructions, wherein when the instructions are executed by a processor, the instructions cause a system to:

capture a noise in a working environment;

generate a noise cancellation signal based on a list of user selected elements of the working environment; and

transmit the noise cancellation signal through a speaker to offset the noise.

19. The article comprising the machine readable medium of claim 18, the instructions further cause the system to:

adjust the noise cancellation signal for distortions.

20. The article comprising the machine readable medium of claim 18, the instructions further cause the system to:

adjust the noise cancellation signal for a delay in transmitting the noise cancellation signal to a user.