Audio framework extension for acoustic feedback suppression

• US 10,154,149 B1
• Filed: 03/15/2018
• Issued: 12/11/2018
• Est. Priority Date: 03/15/2018
• Status: Active Grant

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola Solutions, Inc.
• Inventors: Gean, Nissim, Yamin, Bar, Carmeli, Avner, Livshits, Pavel
• Primary Examiner(s): Gonzales, April G
• Application Number:
  US15/922,660
• Time in Patent Office: 271 Days
• Field of Search: 455570
• CPC Class Codes: H03G 3/005 Control by a pilot signal H03G3/001 takes precedence
• CPC Class Codes: H03G 3/3005 in amplifiers suitable for low-frequencies, e.g. audio amplifiers H03G3/32, H03G3/34 take precedence
• CPC Class Codes: H03G 3/32 the control being dependent upon ambient noise level or sound level
• CPC Class Codes: H04M 9/082 using echo cancellers echo cancellers per se H04B3/23
• CPC Class Codes: H04M 9/085 using digital techniques H04M9/082 takes precedence
• CPC Class Codes: H04R 2430/01 Aspects of volume control, not necessarily automatic, in sound systems
• CPC Class Codes: H04R 3/02 for preventing acoustic reaction , i.e. acoustic oscillatory feedback specially adapted for hearing aids H04R25/453
• CPC Class Codes: H04R 3/04 for correcting frequency response

Abstract

An audio framework for acoustic feedback suppression. One example portable communication device includes a microphone, a loudspeaker, and an electronic processor. The electronic processor receives an acoustic signal, including an audible component and an ultrasonic component, from the microphone. The electronic processor splits the acoustic signal into a first stream and a second stream identical to the first stream. The electronic processor is removes the ultrasonic component from the first stream to generate a filtered audio stream, and passes the filtered audio stream to a sound server. The electronic processor removes the audible component from the second stream to generate a received ultrasonic stream, and compares the received ultrasonic stream to a transmit ultrasonic stream to determine an acoustic distance. The electronic processor determines an attenuation level based on the acoustic distance, and adjusts an audio component of the portable communication device based on the attenuation level.

Claims

1. A portable communication device comprising:

a microphone;

a loudspeaker; and

an electronic processor coupled to the microphone and the loudspeaker, and configured to

receive an acoustic signal from the microphone, the acoustic signal including an audible component and an ultrasonic component;

split the acoustic signal into a first stream and a second stream identical to the first stream;

remove the ultrasonic component from the first stream to generate a filtered audio stream;

pass the filtered audio stream to a sound server;

remove the audible component from the second stream to generate a received ultrasonic stream;

compare the received ultrasonic stream to a transmit ultrasonic stream to determine an acoustic distance;

determine an attenuation level based on the acoustic distance; and

adjust an audio component of the portable communication device based on the attenuation level.

2. The portable communication device of claim 1, further comprising:

a hardware abstraction layer coupled to the electronic processor and the microphone;

wherein the electronic processor is further configured to receive the acoustic signal from the microphone via the hardware abstraction layer.

3. The portable communication device of claim 1, wherein the electronic processor is further configured to:

adjust the gain of the second stream based on a predefined input gain to generate an adjusted second stream; and

remove the audible component from the second stream to generate a received ultrasonic stream by removing the audible component from the adjusted second stream.

4. The portable communication device of claim 1, wherein the electronic processor is further configured to remove the ultrasonic component from the first stream to generate a filtered audio stream by passing the first stream through a low pass filter.

5. The portable communication device of claim 1, wherein the electronic processor is further configured to remove the audible component from the second stream to generate a received ultrasonic stream by passing the second stream through a high pass filter.

6. The portable communication device of claim 1, wherein the electronic processor is further configured to pass the filtered audio stream to a sound server of the portable communication device by passing the filtered audio stream to an audio flinger of the portable communication device.

7. The portable communication device of claim 1, wherein the electronic processor is further configured to adjust an audio component of the portable communication device by adjusting at least one of the group consisting of a loudspeaker volume and a microphone sensitivity.

8. The portable communication device of claim 1, wherein the electronic processor is further configured to:

mix, with the sound server, the transmit ultrasonic stream with an audio stream received from an application to generate a combined audio stream;

split the combined audio stream into a first combined audio stream and a second combined audio stream identical to the first combined audio stream;

extract the audio stream from the first combined audio stream;

extract the transmit ultrasonic stream from the second combined audio stream;

adjust the gain of the audio stream based on a general volume control of the portable communication device to generate an adjusted audio stream;

mix the transmit ultrasonic stream and the adjusted audio stream to create an output audio stream; and

pass the output audio stream to a hardware abstraction layer for output via the loudspeaker.

9. The portable communication device of claim 8, wherein the electronic processor is further configured to:

adjust the gain of the transmit ultrasonic stream based on a predefined output gain to generate an adjusted transmit ultrasonic stream; and

create the output audio stream by mixing the adjusted transmit ultrasonic stream and the adjusted audio stream.

10. A method for providing acoustic feedback suppression in a portable communication device, the method comprising:

receiving an acoustic signal from a microphone of the portable communication device, the acoustic signal including an audible component and an ultrasonic component;

splitting, with an electronic processor, the acoustic signal into a first stream and a second stream identical to the first stream;

removing the ultrasonic component from the first stream to generate a filtered audio stream;

passing the filtered audio stream to a sound server of the portable communication device;

removing the audible component from the second stream to generate a received ultrasonic stream;

comparing the received ultrasonic stream to a transmit ultrasonic stream to determine an acoustic distance;

determining an attenuation level based on the acoustic distance; and

adjusting an audio component of the portable communication device based on the attenuation level.

11. The method of claim 10, wherein receiving an acoustic signal from a microphone of the portable communication device includes receiving an acoustic signal at a hardware abstraction layer of the portable communication device.

12. The method of claim 10, further comprising:

adjusting the gain of the second stream based on a predefined input gain to generate an adjusted second stream;

wherein removing the audible component from the second stream to generate a received ultrasonic stream includes removing the audible component from the adjusted second stream.

13. The method of claim 10, wherein removing the ultrasonic component from the first stream to generate a filtered audio stream includes passing the first stream through a low pass filter.

14. The method of claim 10, wherein removing the audible component from the second stream to generate a received ultrasonic stream includes passing the second stream through a high pass filter.

15. The method of claim 10, wherein passing the filtered audio stream to a sound server of the portable communication device includes passing the filtered audio stream to an audio flinger of the portable communication device.

16. The method of claim 10, wherein adjusting an audio component of the portable communication device includes adjusting at least one of the group consisting of a loudspeaker volume and a microphone sensitivity.

17. The method of claim 10, further comprising:

mixing, with the sound server, the transmit ultrasonic stream with an audio stream received from an application to generate a combined audio stream;

splitting the combined audio stream into a first combined audio stream and a second combined audio stream identical to the first combined audio stream;

extracting the audio stream from the first combined audio stream;

extracting the transmit ultrasonic stream from the second combined audio stream;

adjusting the gain of the audio stream based on a general volume control of the portable communication device to generate an adjusted audio stream;

mixing the transmit ultrasonic stream and the adjusted audio stream to create an output audio stream; and

passing the output audio stream to a hardware abstraction layer for output via a loudspeaker of the portable communication device.

18. The method of claim 17, further comprising:

adjusting the gain of the transmit ultrasonic stream based on a predefined output gain to generate an adjusted transmit ultrasonic stream;

wherein creating the output audio stream includes mixing the adjusted transmit ultrasonic stream and the adjusted audio stream.