Audio processing circuit and audio processing method

Abstract

An audio processing circuit includes at least one audio filter, at least one adaptive non-active noise control (non-ANC) filter, and a leakage detection circuit. The at least one audio filter controls an output signal for an audio function. The at least one adaptive non-ANC filter generates at least one non-anti-noise signal according to an audio playback signal. The leakage detection circuit performs leakage detection according to a first input signal and a second input signal, and adjusts the at least one adaptive non-ANC filter according to a leakage detection result, wherein the first input signal is indicative of noise signal signature, and the second input signal is derived from an error signal output by an error microphone that picks up remnant noise resulting from the audio function.

Claims

1. An audio processing circuit, comprising: at least one audio filter for controlling an output signal for an audio function; at least one adaptive inactive noise reduction filter for generating at least one non-noise-cancelled signal based on an audio playback signal; and a leakage detection circuit for performing leakage detection based on a first input signal and a second input signal, and adjusting the at least one adaptive inactive noise reduction filter based on a leakage detection result, wherein the first input signal indicates noise signal characteristics, and the second input signal originates from an error signal obtained by an error microphone picking up residual noise generated by the audio function.

2. The audio processing circuit as described in claim 1, wherein the first input signal originates from a reference signal output by a reference microphone picking up ambient noise.

3. The audio processing circuit as claimed in claim 1, wherein the first input signal originates from an estimated signal of a noise signal at the location where the audio function occurs.

4. The audio processing circuit as claimed in claim 1, wherein the at least one audio filter includes an adaptive filter, and the leakage detection circuit is further configured to adjust the adaptive filter based on the leakage detection result.

5. The audio processing circuit as claimed in claim 1, wherein the at least one adaptive non-active noise reduction filter comprises: an adaptive audio equalization filter for receiving the audio playback signal and generating an audio equalization signal based on the audio playback signal; and the audio processing circuit further comprises: a first combining circuit for combining the output signal and the audio equalization signal.

6. The audio processing circuit as claimed in claim 5, wherein the at least one adaptive non-active noise reduction filter further comprises: an adaptive audio signal compensation filter for receiving the audio equalization signal and generating an audio signal compensation signal based on the audio equalization signal; and the audio processing circuit further comprises: a second combining circuit for combining the error signal and the audio signal compensation signal.

7. The audio processing circuit as claimed in claim 1, wherein the at least one adaptive non-active noise reduction filter further comprises: an adaptive audio signal compensation filter for receiving the audio playback signal and generating an audio signal compensation signal based on the audio playback signal; and the audio processing circuit further comprises: a combining circuit for combining the error signal and the audio signal compensation signal.

8. The audio processing circuit as claimed in claim 1, wherein the at least one adaptive non-active noise reduction filter includes an adaptive filter, the adaptive filter includes a plurality of static filters, and the leakage detection circuit is configured to select one of the plurality of static filters as an enabled filter based on the leakage detection result.

9. The audio processing circuit as claimed in claim 1, wherein the audio processing circuit is an active noise reduction circuit, each of the at least one audio filter is an active noise reduction filter, the output signal is a noise cancellation signal, and the audio function is noise reduction; or each of the at least one audio filter is a transparency filter.

10. An audio processing method, comprising: controlling an output signal for an audio function via at least one audio filter; generating at least one non-noise-canceling signal based on an audio playback signal via at least one adaptive inactive noise reduction filter; performing leak detection based on a first input signal and a second input signal, wherein the first input signal indicates noise signal characteristics and the second input signal originates from an error signal obtained by an error microphone picking up residual noise generated by the audio function; and adjusting the at least one adaptive inactive noise reduction filter based on a leak detection result.

11. The audio processing method as described in claim 10, wherein the first input signal originates from a reference signal output by a reference microphone picking up ambient noise.

12. The audio processing method as described in claim 10, wherein the first input signal originates from an estimated signal of a noise signal at the location where the audio function occurs.

13. The audio processing method as claimed in claim 10, wherein the at least one audio filter includes an adaptive filter, and the audio processing method further includes: adjusting the adaptive filter based on the leak detection result.

14. The audio processing method as claimed in claim 10, wherein the at least one adaptive non-active noise reduction filter comprises: an adaptive audio equalization filter for receiving the audio playback signal and generating an audio equalization signal based on the audio playback signal; and the audio processing method further comprises: combining the output signal and the audio equalization signal.

15. The audio processing method as claimed in claim 14, wherein the at least one adaptive non-active noise reduction filter further comprises: an adaptive audio signal compensation filter for receiving the audio equalization signal and generating an audio signal compensation signal based on the audio equalization signal; and the audio processing method further comprises: combining the error signal and the audio signal compensation signal.

16. The audio processing method as claimed in claim 10, wherein the at least one adaptive non-active noise reduction filter further comprises: an adaptive audio signal compensation filter for receiving the audio playback signal and generating an audio signal compensation signal based on the audio playback signal; and the audio processing method further comprises: combining the error signal and the audio signal compensation signal.

17. The audio processing method as claimed in claim 10, wherein the at least one adaptive non-active noise reduction filter includes an adaptive filter, the adaptive filter includes a plurality of static filters, and the step of adjusting the at least one adaptive non-active noise reduction filter according to the leakage detection result includes: selecting one of the plurality of static filters as an enabled filter according to the leakage detection result.

18. The audio processing method as claimed in claim 10, wherein the audio processing method is an active noise reduction method, each of the at least one audio filter is an active noise reduction filter, the output signal is a noise cancellation signal, and the audio function is noise reduction; or each of the at least one audio filter is a transparency filter.

19. An audio processing circuit, comprising: at least one adaptive inactive noise reduction filter for generating at least one non-noise-cancelled signal based on an audio playback signal; and a leakage detection circuit for performing leakage detection based on a first input signal and a second input signal, and adjusting the at least one adaptive inactive noise reduction filter based on a leakage detection result, wherein the first input signal indicates noise signal characteristics, and the second input signal originates from an error signal; wherein the adjustment of the at least one adaptive inactive noise reduction filter does not require the use of a least mean square-based algorithm.

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