Granted Patent B2

US 9,124,219 · App. 13/166,600 · Granted Sep 1, 2015

Abstract

Claims (42)

1. An audio driver comprising:

a distortion detector coupled between an amplifier and a loudspeaker and configured to detect a distortion signal generated by the loudspeaker while the loudspeaker is being used to deliver an audio signal from the amplifier; and

a distortion compensator coupled prior to the amplifier and configured to compensate for the distortion signal;

wherein the distortion detector is configured to analyze the energy at one of a plurality of frequency bands to determine whether distortion exists.

2. The audio driver of claim 1 further comprising:

a resistor connected in series between the amplifier and the loudspeaker; and

a differential amplifier coupled to the distortion detector and configured to measure a voltage drop across the resistor.

3. The audio driver of claim 2 , wherein the distortion detector comprises an analog to digital converter (ADC) operable to digitize the voltage across the resistor.

4. The audio driver of claim 2 , wherein the distortion detector comprises a fast Fourier transform operable to convert the voltage across the resistor into frequency data.

5. The audio driver of claim 4 , wherein the distortion detector is operable to measure a root-mean-square (RMS) power within the frequency data.

6. The audio driver of claim 5 , wherein the distortion detector comprises an analyzer operable to detect distortion from the energy within the frequency data.

7. The audio driver of claim 1 , wherein the distortion compensator comprises a dynamic range compressor.

8. The audio driver of claim 1 , wherein the distortion compensator comprises:

an analyzer;

a phase modifier; and

a synthesizer.

9. The audio driver of claim 8 wherein the analyzer is configured to identify a distortion signature in an energy spectrum.

10. The audio driver of claim 8 wherein the phase modifier is configured to process frequency data, amplitude data and phase data for each track of a plurality of tracks and to determine an optimal phase for each track in order to minimize a peak amplitude of an audio signal.

11. The audio driver of claim 8 wherein the synthesizer is configured to interpolate frequency data, amplitude data and optimal phase data across a frame of audio data and to construct an audio signal from the interpolated data.

12. The audio driver of claim 1 , wherein the distortion compensator comprises a digital clipper or an analog clipper.

13. A method of compensating for distortion in an audio signal comprising:

detecting the current between an output driver and a loudspeaker;

converting the current to a voltage;

determining whether a distortion signal generated by the loudspeaker exists from the voltage; and

compensating for the distortion signal;

wherein determining whether the distortion signal generated by the loudspeaker exists from the voltage comprises:

digitizing the voltage into digitized voltage data; transforming the digitized voltage data into frequency data;

measuring the energy at each of a plurality of frequency bands in the frequency data; and

analyzing the energy at one of the frequency bands to determine whether distortion exists.

14. The method of claim 13 , wherein compensating for the distortion signal comprises applying dynamic range compression.

15. The method of claim 13 , wherein compensating for the distortion signal comprises dynamically adjusting a gain by interpolating frequency data, amplitude data and optimal phase data across a frame and constructing a new audio signal from the interpolated data.

16. The method of claim 13 , wherein compensating for the distortion signal comprises determining an optimal phase of the audio signal for each track of a plurality of tracks.

17. A method of compensating for distortion in an audio signal comprising:

detecting the current between an output driver and a loudspeaker;

converting the current to a voltage:

determining whether a distortion signal generated by the loudspeaker exists from the voltage, comprising:

digitizing the voltage into digitized voltage data:

transforming the digitized voltage data into frequency data;

measuring the energy at each of a plurality of frequency bands in the frequency data; and

analyzing the energy at one of the frequency bands to determine whether distortion exists; and

compensating for the distortion signal.

18. The method of claim 17 wherein converting the current to a voltage comprises reading a voltage signal across a serial resistance.

Assignments (8)