In-vehicle communication signal processing

Patent metadata

Field	Value
Publication number	US-2017193976-A1
Application number	US-201615216577-A
Country	US
Kind code	A1
Filing date	Jul 21, 2016
Priority date	Dec 30, 2015
Publication date	Jul 6, 2017
Grant date	—

Abstract

A system includes a feedback filter configured to receive an audio signal from a microphone and to process the audio signal based on a feedback path between a loudspeaker and the microphone. The system also includes an adaptive filter coupled to the feedback filter. The system further includes a signal combiner coupled to the microphone and to the adaptive filter.

First claim

What is claimed is:

1 . A system comprising:
a feedback filter configured to receive an audio signal from a microphone and to process the audio signal based on a feedback path between a loudspeaker and the microphone; an adaptive filter coupled to the feedback filter; and a signal combiner coupled to the microphone and to the adaptive filter.

2 . The system of claim 1 , further including a second feedback filter configured to process the audio signal responsive to a second feedback path between a second loudspeaker and the microphone, wherein the second feedback path is distinct from the feedback path, and wherein the adaptive filter is further coupled to the second feedback filter.

3 . The system of claim 2 , wherein the feedback filter is configured to apply a first delay corresponding to a first feedback path between the loudspeaker and the microphone, and wherein the second feedback filter is configured to apply a second delay corresponding to the second feedback path.

4 . The system of claim 2 , further comprising:
a first adder having a first input coupled to an output of the signal combiner, a second input coupled to receive a first surround sound signal, and an output coupled to the loudspeaker; and a second adder having a first input coupled to the signal combiner, a second input coupled to receive a second surround sound signal, and an output coupled to the second loudspeaker.

5 . The system of claim 1 , further including a second feedback filter configured to process a second audio signal responsive to a second feedback path between a second loudspeaker and the microphone, and wherein the adaptive filter is further coupled to the second feedback filter.

6 . The system of claim 5 , wherein the feedback filter, the second feedback filter, the adaptive filter, and the signal combiner are included in a feedback cancellation unit, and further comprising a second feedback cancellation unit coupled to a second microphone, wherein the second feedback cancellation unit comprises:
a third feedback filter configured to process the audio signal from the microphone responsive to a third feedback path between the loudspeaker and the second microphone; a fourth feedback filter configured to process the second audio signal from the second microphone responsive to a fourth feedback path between the second loudspeaker and the second microphone; and a second adaptive filter coupled to the third feedback filter and the fourth feedback filter; and a second signal combiner coupled to the second microphone and to the second feedback cancellation unit.

7 . The system of claim 1 , wherein the adaptive filter is coupled to the feedback filter via a delay element.

8 . The system of claim 1 , wherein the feedback path includes an acoustic path between the loudspeaker and the microphone.

9 . The system of claim 8 , further comprising a feedback cancellation unit configured to:
determine an impulse response of the acoustic path based on input received by the microphone responsive to a calibration signal from the loudspeaker during a configuration mode; and set the feedback filter based on the impulse response.

10 . The system of claim 1 , wherein the feedback filter, the adaptive filter, and the signal combiner are integrated into a mobile device.

11 . A method for in-vehicle communication, the method comprising:
receiving an audio signal from a microphone of a vehicle; processing the audio signal to at least partially cancel a feedback portion of the audio signal, the feedback portion corresponding to an output of a loudspeaker of the vehicle, wherein processing the audio signal includes:
generating a filtered signal based on the audio signal;
generating a cancellation signal at least partially based on the filtered signal; and
adaptively filtering the cancellation signal to generate a filtered cancellation signal; and
combining the filtered cancellation signal with the audio signal to generate a modified audio signal.

12 . The method of claim 11 , further comprising processing the modified audio signal to generate an input signal for the loudspeaker.

13 . The method of claim 12 , wherein the microphone is at a first location proximate to a first occupant of the vehicle, wherein the loudspeaker is at a second location proximate to a second occupant of the vehicle, wherein the audio signal includes a voice portion that corresponds to speech of the first occupant, and wherein the input signal causes the loudspeaker to output a synthesized version of the speech of the first occupant at the second location proximate to the second occupant.

14 . The method of claim 12 , wherein combining the filtered cancellation signal with the audio signal attenuates one or more loudspeaker output signals that are received at the microphone without substantial attenuation of a voice portion of the audio signal.

15 . The method of claim 12 , wherein processing the modified audio signal includes adding a surround sound component for the loudspeaker to the modified audio signal.

16 . The method of claim 15 , wherein processing the audio signal includes at least partially cancelling a second feedback portion of the audio signal to generate a second filtered signal, the second feedback portion corresponding to an output of a second loudspeaker of the vehicle, wherein the cancellation signal is further based on the second filtered signal.

17 . The method of claim 16 , wherein processing the modified audio signal includes adding a second surround sound component for the second loudspeaker to the modified audio signal.

18 . The method of claim 16 , wherein processing the audio signal includes:
filtering the audio signal at a first filter having a first transfer characteristic corresponding to a first feedback path between the loudspeaker and the microphone to generate the filtered signal; filtering the audio signal at a second filter having a second transfer characteristic corresponding to a second feedback path between the second loudspeaker and the microphone to generate the second filtered signal; and combining the filtered signal and the second filtered signal.

19 . The method of claim 16 , wherein processing the audio signal includes:
delaying the audio signal with a first delay corresponding to a first feedback path between the loudspeaker and the microphone to generate the filtered signal; delaying the audio signal with a second delay corresponding to a second feedback path between the second loudspeaker and the microphone to generate the second filtered signal; and combining the filtered signal and the second filtered signal.

20 . A non-transitory computer-readable medium comprising instructions for in-vehicle communication, the instructions, when executed by a processor, cause the processor to perform operations comprising:
processing an audio signal from a microphone of a vehicle to at least partially cancel a feedback portion of the audio signal, the feedback portion corresponding to an output of a loudspeaker of the vehicle, wherein processing the audio signal includes:
generating a filtered signal;
generating a cancellation signal at least partially based on the filtered signal; and
adaptively filtering the cancellation signal to generate a filtered cancellation signal; and
combining the filtered cancellation signal with the audio signal to generate a modified audio signal.

21 . The non-transitory computer-readable medium of claim 20 , the operations

Assignees

• Qualcomm Inc

Inventors

• Mohammad Asif
• Narayanaswamy Sreekanth
• Heimbigner Wade
• Visser Erik

Classifications

• G10K11/178 Primary

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

• G10K2210/12821

  Rolling noise; Wind and body noise · CPC title

• G10K11/17854

  the filter being an adaptive filter · CPC title

• G10K11/17875 Primary

  using an error signal without a reference signal, e.g. pure feedback · CPC title

• G10K11/17813

  characterised by the analysis of the acoustic paths, e.g. estimating, calibrating or testing of transfer functions or cross-terms · CPC title