SYSTEM AND METHOD FOR REDUCING RUB AND BUZZ DISTORTION

• US 20110188670A1
• Filed: 12/08/2010
• Published: 08/04/2011
• Est. Priority Date: 12/23/2009
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Conexant Systems, LLC (Synaptics Incorporated)
• Inventors: Regev, Shlomi I., Thormundsson, Trausti, Lau, Harry K., Wihardja, James W.
• Granted Patent: US 9,497,540 B2
• Time in Patent Office: Days
• US Class Current: 381/94.1
• CPC Class Codes: H03G 3/20 Automatic control H03G3/005 takes precedence; combined with volume compression or expansion H03G7/00
• CPC Class Codes: H03G 3/32 the control being dependent upon ambient noise level or sound level
• CPC Class Codes: H03G 5/165 Equalizers; Volume or gain control in limited frequency bands
• CPC Class Codes: H04R 29/001 for loudspeakers H04R29/007 takes precedence
• CPC Class Codes: H04R 3/00 Circuits for transducers , loudspeakers or microphones
• CPC Class Codes: H04R 3/007 Protection circuits for transducers

Abstract

An audio driver with reduced rub and buzz distortion that includes a digital processing module. A digital to audio converter (DAC) operable to receive a digital audio signal supplied by the digital processing module. One or more analog driver stages operable to receive an analog audio signal supplied by the DAC. A peak amplitude compressor.

Claims

1. An audio driver with reduced rub and buzz distortion comprising:

a digital processing module;

a digital to audio converter (DAC) operable to receive a digital audio signal supplied by the digital processing module;

one or more analog driver stages operable to receive an analog audio signal supplied by the DAC; and

a peak amplitude compressor.

2. The audio driver of claim 1, wherein the peak amplitude compressor comprises a clipping circuit coupled to the DAC and the analog driver stages.

3. The audio driver of claim 1, wherein the peak amplitude compressor comprises an analog automatic gain control (AGC) circuit coupled to the DAC and the analog driver stages.

4. The audio driver of claim 1, wherein the peak amplitude compressor comprises a digital AGC circuit coupled to the digital processing module and the DAC.

5. The audio driver of claim 1, wherein the peak amplitude compressor comprises a phase modification circuit.

6. The audio driver of claim 5, wherein the phase modification circuit comprises:

an analysis module;

a phase modification module; and

a synthesis module.

7. A method for reducing rub and buzz distortion in a loud speaker comprising:

determining a plurality of sinusoidal tracks in an audio signal;

determining a phase, an amplitude and a frequency for each track;

determining an optimal phase for each track that minimizes a peak displacement of the loudspeaker; and

synthesizing an output audio signal based on the optimal phase, the amplitude and the frequency of one or more tracks.

8. The method of claim 7 further comprising zeroing the amplitude of tracks with energy levels below a predetermined level.

9. The method of claim 7 further comprising determining a peak amplitude of the output audio signal.

10. The method of claim 9 further comprising attenuating the amplitudes of all the tracks if the peak amplitude is above a given threshold.

11. An audio driver comprising:

a digital processing module;

a digital to audio converter (DAC) operable to receive a digital audio signal supplied by the digital processing module;

one or more analog driver stages operable to receive an analog audio signal supplied by the DAC; and

means for reducing rub and buzz distortion.

12. The audio driver of claim 11, wherein the means for reducing rub and buzz distortion comprises a peak amplitude compressor.

13. The audio driver of claim 11, wherein the means for reducing rub and buzz distortion comprises a clipping circuit coupled to the DAC and the analog driver stages.

14. The audio driver of claim 11, wherein the means for reducing rub and buzz distortion comprises an analog automatic gain control (AGC) circuit coupled to the DAC and the analog driver stages.

15. The audio driver of claim 11, wherein the means for reducing rub and buzz distortion comprises a digital AGC circuit coupled to the digital processing module and the DAC.

16. The audio driver of claim 11, wherein the means for reducing rub and buzz distortion comprises a phase modification circuit.

17. The audio driver of claim 16, wherein the phase modification circuit comprises an analysis module.

18. The audio driver of claim 17, wherein the phase modification circuit further comprises a phase modification module coupled to the analysis module and the digital processing module.

19. The audio driver of claim 18, wherein the phase modification circuit further comprises a synthesis module coupled to the phase modification module.

20. The audio driver of claim 19, further comprising an automatic gain control circuit coupled to the synthesis module.