ADAPTIVE FILTERING

• US 20150287400A1
• Filed: 04/02/2015
• Published: 10/08/2015
• Est. Priority Date: 04/07/2014
• Status: Active Grant

• Current Assignee: Harman Becker Automotive Systems GmbH (Samsung Electronics Co. Ltd.)
• Original Assignee: Harman Becker Automotive Systems GmbH (Samsung Electronics Co. Ltd.)
• Inventors: CHRISTOPH, Markus
• Granted Patent: US 10,460,716 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 3/165 Management of the audio stream, e.g. setting of volume, audio stream path
• CPC Class Codes: G10K 11/17817 between the output signals and the error signals, i.e. secondary path
• CPC Class Codes: G10K 11/17854 the filter being an adaptive filter
• CPC Class Codes: G10K 11/17879 using both a reference signal and an error signal
• CPC Class Codes: H04R 2499/13 Acoustic transducers and sound field adaptation in vehicles
• CPC Class Codes: H04S 7/301 Automatic calibration of stereophonic sound system, e.g. with test microphone
• CPC Class Codes: H04S 7/307 Frequency adjustment, e.g. tone control H04S7/301 takes precedence

Abstract

A system and method include filtering with controllable transfer functions in signal paths upstream of K≧1 output paths and downstream of Q≧1 source input paths, and controlling with filter control signals of the controllable transfer functions according to an adaptive control algorithm based on error signals on M≧1 error input paths and source input signals on the Q source input paths. The system and method further include at least one loudspeaker-room-microphone constraint.

Claims

1. A system comprising:

K≧

1 output paths,

M≧

1 error input paths,

Q≧

1 source input paths,

K filter modules that are arranged in signal paths upstream of the K output paths and downstream of the Q source input paths and that have controllable transfer functions, and

K filter control modules that are arranged in signal paths downstream of the M error input paths and downstream of the Q source input paths and that are configured to control the transfer functions of the K filter modules according to an adaptive control algorithm based on error signals on the M error input paths and source input signals on the Q source input paths, wherein

the system further comprises at least one loudspeaker-room-microphone constraint.

2. The system of claim 1, wherein the at least one loudspeaker-room-microphone constraint is at least one of the following:

a frequency constraint that is configured to compensate for differences in acoustic behavior between loudspeakers of a loudspeaker-room-microphone system, and

a spatial constraint that is configured to weight the error signals on the M error input paths according to a position of microphones in the loudspeaker-room-microphone system.

3. The system of claim 2, wherein the adaptive control algorithm is configured to provide the spatial constraint.

4. The system of claim 2, further comprising a spatial filter module that is configured to provide the spatial constraint, wherein

the spatial filter module is arranged in the M error input paths;

and

the spatial filter module has a transfer function configured to weight the error signals on the K error input paths according to the position of the microphones in the loudspeaker-room-microphone system.

5. The system of claim 2, wherein the adaptive control algorithm is configured to provide the frequency constraint.

6. The system of claim 5, wherein the frequency constraint is configured to provide crossover filtering.

7. The system of claim 2, further comprising K frequency filter modules that are configured to provide the frequency constraint, wherein

the K frequency filter modules are arranged in the signal paths upstream of the K output paths and downstream of the Q source input signal paths;

and

the K frequency filter modules have transfer functions configured to compensate for differences in the acoustic behavior between the loudspeakers of the loudspeaker-room-microphone system.

8. A method comprising:

filtering with controllable transfer functions in signal paths upstream of K≧

1 output paths and downstream of Q≧

1 source input paths, and

controlling with filter control signals of the controllable transfer functions according to an adaptive control algorithm based on error signals on M≧

1 error input paths and source input signals on the Q source input paths, wherein

the method further comprises at least one loudspeaker-room-microphone constraint.

9. The method of claim 8, wherein the at least one loudspeaker-room-microphone constraint is at least one of the following:

a frequency constraint that is configured to compensate for differences in acoustic behavior between loudspeakers of a loudspeaker-room-microphone system, and

a spatial constraint that is configured to weight the error signals on the K error input paths according to a position of microphones in the loudspeaker-room-microphone system.

10. The method of claim 9, wherein the adaptive control algorithm is configured to provide the spatial constraint.

11. The method of claim 9, further comprising a spatial filtering that is configured to provide the spatial constraint, wherein

spatial filtering is applied in the signal paths upstream of the K output paths and downstream of the Q source input signal paths, and

spatial filtering is performed with a transfer function configured to weight the error signals according to the position of the microphones in the loudspeaker-room-microphone system.

12. The method of claim 9, wherein the adaptive control algorithm is configured to provide the frequency constraint.

13. The method of claim 12, wherein the frequency constraint is configured to provide crossover filtering.

14. The method of claim 9, further comprising frequency filtering that is configured to provide the frequency constraint, wherein

frequency filtering is applied in the signal paths upstream of the K output paths and downstream of the Q source input paths, and

frequency filtering is performed with transfer functions configured to compensate for differences in the acoustic behavior between the loudspeakers of the loudspeaker-room-microphone system.

15. A system comprising:

at least one K output path;

at least one M error input path;

at least one Q source input path;

at least one loudspeaker-room-microphone constraint;

a plurality of K filter modules that are arranged in signal paths upstream of the at least one K output path and downstream of the at least one Q source input path and that have controllable transfer functions; and

a plurality of K filter control modules that are arranged in signal paths downstream of the at least one M error input path and downstream of the at least one Q source input path and that are configured to control the transfer functions of the plurality of K filter modules according to an adaptive control algorithm based on error signals on the at least one M error input path and source input signals on the at least one Q source input path.

16. The system of claim 15, wherein the at least one loudspeaker-room-microphone constraint is at least one of the following:

a frequency constraint that is configured to compensate for differences in acoustic behavior between loudspeakers of a loudspeaker-room-microphone system; and

a spatial constraint that is configured to weight the error signals on the M error input paths according to a position of microphones in the loudspeaker-room-microphone system.

17. The system of claim 16, wherein the adaptive control algorithm is configured to provide the spatial constraint.

18. The system of claim 16, further comprising a spatial filter module that is configured to provide the spatial constraint, wherein

the spatial filter module is arranged in the M error input paths;

and

the spatial filter module has a transfer function configured to weight the error signals on the K error input paths according to the position of the microphones in the loudspeaker-room-microphone system.

19. The system of claim 16, wherein the adaptive control algorithm is configured to provide the frequency constraint.

20. The system of claim 16, further comprising K frequency filter modules that are configured to provide the frequency constraint, wherein

the K frequency filter modules are arranged in the signal paths upstream of the K output paths and downstream of the Q source input signal paths;

and

the K frequency filter modules have transfer functions configured to compensate for differences in the acoustic behavior between the loudspeakers of the loudspeaker-room-microphone system.