Method and device for reducing acoustic feedback

Patent metadata

Field	Value
Publication number	US-9357301-B2
Application number	US-201214358283-A
Country	US
Kind code	B2
Filing date	Oct 17, 2012
Priority date	Nov 15, 2011
Publication date	May 31, 2016
Grant date	May 31, 2016

Abstract

Acoustic feedback in an audio device is reduced or eliminated via a feedback compensator. The feedback compensator disposes of at least one adaptive filter whose adaptation is governed by a step-size parameter μ. A step-size parameter μ of the adaptive filter is set at a high level to eliminate acoustic feedback and the parameter μ is decreased when a critical excitation signal is detected. This way to proceed allows for efficient elimination of feedback whistling while required environment signals are retained.

First claim

The invention claimed is:

1. A method of reducing acoustic feedback of an audio device by a feedback compensator, the feedback compensator having at least one adaptive filter, the method comprising the steps of:
setting a step-size parameter p of the adaptive filter at a high level to eliminate acoustic feedback;
using a feedback detector to detect a critical excitation signal being a tonal signal, wherein the tonal signal is a microphone signal which is received by the feedback detector; and
when the critical excitation signal is detected, decreasing the step-size parameter p;
wherein the step-size parameter p controls an adaptation speed of the adaptive filter and wherein the step-size parameter p is set at 0.06 or more to eliminate acoustic feedback.

2. The method according to claim 1 , which comprises controlling the step-size parameter p with a step-size controller.

3. The method according to claim 1 , which comprises processing signals with a signal processing unit prior to the signals being fed to an audio output.

4. The method according to claim 1 , which comprises using a detector for correlated signals to detect the critical excitation signal.

5. The method according to claim 1 , which comprises carrying out a frequency decomposition of excitation signals into frequency subbands, and selectively applying the method to at least one subband.

6. The method according to claim 1 , which comprises employing the method for stabilizing adaption of an adaptive filter.

7. An audio device, comprising:
a feedback compensator for reducing acoustic feedback, said feedback compensator containing at least one adaptive filter controlled with a step-size parameter p;
a feedback detector configured to detect a critical excitation signal being a tonal signal, wherein the tonal signal is a microphone signal which is received by said feedback detector; and
a step-size controller configured for setting the step-size parameter p of said adaptive filter at a relatively high level to eliminate acoustic feedback;
said step-size controller configured for decreasing the step-size parameter p when said feedback detector detects the critical excitation signal;
wherein the critical signal is a tonal signal; and
wherein the step-size parameter p controls an adaptation speed of said adaptive filter and wherein the step-size parameter p is set at 0.06 or more to eliminate acoustic feedback.

8. The audio device according to claim 7 , further comprising a step-size controller configured for controlling the step-size parameter p.

9. The audio device according to claim 7 , further comprising a signal processing unit for processing signals before the signals are fed to an audio output.

10. The audio device according to claim 7 , further comprising a detector for correlated signals to detect the critical excitation signal.

11. The audio device according to claim 7 , configured for operation to perform a frequency decomposition of excitation signals into subbands.

Assignees

• Sivantos Pte Ltd

Inventors

• Pape Sebastian
• Wurzbacher Tobias

Classifications

• H03F1/36

  in discharge-tube amplifiers · CPC title

• H04R25/453

  electronically · CPC title

• H03G3/001

  Digital control of analog signals · CPC title

• G10K11/1784

  Physics · mapped topic

• H04R3/02 Primary

  for preventing acoustic reaction {, i.e. acoustic oscillatory feedback (specially adapted for hearing aids H04R25/453)} · CPC title