Variable bandwidth delayless subband algorithm for broadband active noise control system

Patent metadata

Field	Value
Publication number	US-9837065-B2
Application number	US-201414563199-A
Country	US
Kind code	B2
Filing date	Dec 8, 2014
Priority date	Dec 8, 2014
Publication date	Dec 5, 2017
Grant date	Dec 5, 2017

Abstract

An active noise control (ANC) system includes a speaker and one or more processors programmed to implement a delayless subband filtered-x least mean square control algorithm. The algorithm includes a variable bandwidth discrete Fourier transform filter bank having a number of subbands such that the system, in response to a broadband white noise reference signal indicative of road noise in the vehicle, exhibits a uniform gain spectrum across a frequency range defined by the subbands and partially cancels the road noise via output of the speaker.

First claim

What is claimed is:

1. An active noise control system for a vehicle comprising:
speakers;
sensors configured to detect broadband white noise reference signals indicative of road noise; and
a processor including a delayless subband filtered-x least mean square control algorithm that comprises a variable bandwidth discrete Fourier transform filter bank having a number of subbands, the processor configured to execute the delayless subband filtered-x least mean square control algorithm to process the broadband white noise reference signals and generate output exhibiting uniform gain spectrum across a frequency range defined by the subbands to partially cancel the road noise via the speakers.

2. The system of claim 1 , wherein the delayless subband filtered-x least mean square control algorithm further comprises a uniform filter bank and wherein center frequencies of the variable bandwidth discrete Fourier transform filter bank are offset from center frequencies of the uniform filter bank by one half a bandwidth of the uniform filter bank.

3. The system of claim 2 , wherein a bandwidth of the variable bandwidth discrete Fourier transform filter bank is less than the bandwidth of the uniform filter bank.

4. The system of claim 2 , wherein a bandwidth of the variable bandwidth discrete Fourier transform filter bank is at least one half the bandwidth of the uniform filter bank.

5. A method for actively controlling noise in an active noise control (ANC) system comprising speakers, sensors, and one or more processors including a delayless subband filtered-x least mean square control algorithm that comprises a variable bandwidth discrete Fourier transform filter bank having a number of subbands, the method comprising:
detecting by the sensors broadband white noise reference signals indicative of road noise and having an audible frequency range of 20 Hz to 20 kHz; and
executing by the one or more processors the delayless subband filtered-x least mean square control algorithm to process the broadband white noise reference signals, and generate output exhibiting uniform gain spectrum across a frequency range defined by the subbands to partially cancel the road noise via the speakers.

6. The method of claim 5 , wherein the delayless subband filtered-x least mean square control algorithm further comprises a uniform filter bank and wherein center frequencies of the variable bandwidth discrete Fourier transform filter bank are offset from center frequencies of the uniform filter bank by one half a bandwidth of the uniform filter bank.

7. The method of claim 6 , wherein a bandwidth of the variable bandwidth discrete Fourier transform filter bank is less than the bandwidth of the uniform filter bank.

8. The method of claim 7 , wherein a bandwidth of the variable bandwidth discrete Fourier transform filter bank is at least one half the bandwidth of the uniform filter bank.

9. An active noise control (ANC) system comprising:
a speaker;
sensors configured to detect broadband white noise reference signals indicative of road noise; and
one or more processors including a delayless subband filtered-x least mean square control algorithm that comprises a variable bandwidth discrete Fourier transform filter bank having a number of subbands, the one or more processors being configured to execute the delayless subband filtered-x least mean square control algorithm to process the broadband white noise reference signals and generate output exhibiting uniform gain spectrum across a frequency range defined by the subbands to partially cancel the road noise via the speakers.

10. The system of claim 9 , wherein the delayless subband filtered-x least mean square control algorithm further comprises a uniform filter bank and wherein center frequencies of the variable bandwidth discrete Fourier transform filter bank are offset from center frequencies of the uniform filter bank by one half a bandwidth of the uniform filter bank.

11. The system of claim 10 , wherein a bandwidth of the variable bandwidth discrete Fourier transform filter bank is less than the bandwidth of the uniform filter bank.

12. The system of claim 10 , wherein a bandwidth of the variable bandwidth discrete Fourier transform filter bank is at least one half the bandwidth of the uniform filter bank.

Assignees

• Ford Global Tech Llc
• Univ Cincinnati

Inventors

• Lee Ming-Ran
• Abe Takeshi
• Cheng Ming-Te
• Vanhaaften Frederick Wayne
• Na Liqun
• Lim Teik
• Li Mingfeng
• Sun Guohua
• Feng Tao

Classifications

• G10K2210/12821

  Rolling noise; Wind and body noise · CPC title

• G10K2210/3012

  Algorithms · CPC title

• G10K2210/3053

  Speeding up computation or convergence, or decreasing the computational load · CPC title

• G10K11/178 Primary

  by electro-acoustically regenerating the original acoustic waves in anti-phase · CPC title

• G10K11/17855

  for improving speed or power requirements · CPC title