Adaptive residual feedback suppression

Patent metadata

Field	Value
Publication number	US-9712908-B2
Application number	US-201314074152-A
Country	US
Kind code	B2
Filing date	Nov 7, 2013
Priority date	Nov 5, 2013
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

A hearing aid includes: an input transducer for generating an audio signal; a feedback suppression circuit configured for modelling a feedback path of the hearing aid; a subtractor for subtracting an output signal of the feedback suppression circuit from the audio signal to form a feedback compensated audio signal; a signal processor that is coupled to an output of the subtractor for processing the feedback compensated audio signal to perform hearing loss compensation; and a receiver that is coupled to an output of the signal processor for converting the processed feedback compensated audio signal into a sound signal; wherein the hearing aid further comprises a gain processor for performing gain adjustment of the feedback compensated audio signal based at least on an estimate of a residual feedback signal of the feedback compensated audio signal, wherein the estimate of the residual feedback signal is based at least on the audio signal.

First claim

The invention claimed is:

1. A hearing aid comprising:
an input transducer for generating an audio signal;
a feedback suppression circuit configured for modelling a feedback path of the hearing aid;
a subtractor for subtracting an output signal of the feedback suppression circuit from the audio signal to form a feedback compensated audio signal;
a signal processor that is coupled to an output of the subtractor for processing the feedback compensated audio signal to perform hearing loss compensation; and
a receiver that is coupled to an output of the signal processor for converting the processed feedback compensated audio signal into a sound signal;
wherein the hearing aid further comprises a gain processor for performing gain adjustment of the feedback compensated audio signal based at least on an estimate of a residual feedback signal of the feedback compensated audio signal, wherein the estimate of the residual feedback signal is based at least on the audio signal, and wherein an amount of the gain adjustment is variable in response to a variability of the estimate of the residual feedback signal.

2. The hearing aid according to claim 1 , wherein the feedback suppression circuit is configured during an initialization of the hearing aid, and wherein the estimate of the residual feedback signal is further based on a configuration of the feedback suppression circuit achieved during the initialization of the hearing aid.

3. The hearing aid according to claim 1 , wherein the feedback suppression circuit has a configuration that is variable, and wherein the estimate of the residual feedback signal is further based on a configuration of the feedback suppression circuit as determined during a current operation of the hearing aid.

4. The hearing aid according to claim 1 , wherein the estimate of the residual feedback signal is further based on a gain value of the hearing aid.

5. The hearing aid according to claim 1 , wherein the feedback suppression circuit comprises an adaptive filter.

6. The hearing aid according to claim 1 , wherein the gain processor and the signal processor are configured to respectively perform the gain adjustment and the hearing loss compensation separately.

7. The hearing aid according to claim 1 , wherein the signal processor is configured to perform multi-band hearing loss compensation in a set of frequency bands k, and wherein the estimate of the residual feedback signal comprises estimates of the residual feedback signal in the frequency bands k.

8. The hearing aid according to claim 7 , wherein the estimate of the residual feedback signal includes an estimate of an adaptive broad-band contribution β.

9. A hearing aid comprising:
an input transducer for generating an audio signal;
a feedback suppression circuit configured for modelling a feedback path of the hearing aid;
a subtractor for subtracting an output signal of the feedback suppression circuit from the audio signal to form a feedback compensated audio signal;
a signal processor that is coupled to an output of the subtractor for processing the feedback compensated audio signal to perform hearing loss compensation; and
a receiver that is coupled to an output of the signal processor for converting the processed feedback compensated audio signal into a sound signal;

wherein the hearing aid further comprises a gain processor for performing gain adjustment of the feedback compensated audio signal based at least on an estimate of a residual feedback signal of the feedback compensated audio signal, wherein the estimate of the residual feedback signal is based at least on the audio signal;
wherein the signal processor is configured to perform multi-band hearing loss compensation in a set of frequency bands k, and wherein the estimate of the residual feedback signal comprises estimates of the residual feedback signal in the frequency bands k;
wherein the estimate of the residual feedback signal includes an estimate of an adaptive broad-band contribution β; and
wherein the estimates R k of the residual feedback signal in the respective frequency bands k is given by
| R k |=β|A k ∥B k |

and an amount of the gain adjustment α k is calculated from:

α
k
2

=

1

(

1
+

β
2

⁢



G
k



2

⁢



A
k



2

⁢



B
k



2

)

wherein
β is a scaling term relating the residual feedback signal to a feedback reference,
A k is a feedback reference gain obtained using the feedback suppression circuit, and
B k is a contribution from the audio signal.

10. The hearing aid according to claim 9 , wherein the feedback suppression circuit comprises an adaptive filter, and wherein β is calculated from:

β
=

(

(

c
s

⁢



h
emp

→

*

w
→



)

q

+

(

c
d

⁢

Assignees

• Gn Hearing As

Inventors

• Van Der Werf Erik Cornelis Diederik

Classifications

• H04R25/305

  Self-monitoring or self-testing · CPC title

• H04R25/45

  Prevention of acoustic reaction, i.e. acoustic oscillatory feedback · CPC title

• H04R25/453 Primary

  electronically · CPC title

• H04R1/1091 Primary

  Details not provided for in groups H04R1/1008 - H04R1/1083 · CPC title

• H04R3/002

  Damping circuit arrangements for transducers, e.g. motional feedback circuits · CPC title