Distortion compensation
First Claim
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1. An automotive audio amplifier comprising:
- an acoustic signal processor configured to control gain for at least one channel of a multi-channel audio signal, the gain being controlled according to a gain adjust signal;
a voltage sensor configured to generate a voltage sense signal associated with a battery supply voltage for the amplifier; and
a threshold detector configured to generate the gain adjust signal according to detecting whether an output of the gain circuit exceeds a clipping threshold, the clipping threshold being adjustable according to the voltage sense signal;
where the clipping threshold is adjusted to clip channels of the multi-channel audio signal in accordance with a threshold corresponding to the battery supply voltage at a time of tuning the automotive audio amplifier.
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Abstract
A distortion compensation system minimizes distortion in an audio system by monitoring a supply voltage and adjusting a clipping threshold and/or compression knee. An adjustable gain circuit controls the gain of the audio signal according whether the audio signal exceeds a variable threshold. The variable threshold is adjusted within a threshold range based on the supply voltage. Distortion due to clipping of the audio signal is minimized while available power at any given time is maximized.
164 Citations
22 Claims
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1. An automotive audio amplifier comprising:
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an acoustic signal processor configured to control gain for at least one channel of a multi-channel audio signal, the gain being controlled according to a gain adjust signal; a voltage sensor configured to generate a voltage sense signal associated with a battery supply voltage for the amplifier; and a threshold detector configured to generate the gain adjust signal according to detecting whether an output of the gain circuit exceeds a clipping threshold, the clipping threshold being adjustable according to the voltage sense signal; where the clipping threshold is adjusted to clip channels of the multi-channel audio signal in accordance with a threshold corresponding to the battery supply voltage at a time of tuning the automotive audio amplifier. - View Dependent Claims (2, 3, 4, 5)
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6. An automotive audio system comprising:
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a controller configured to control gain adjustment for each channel of a multi-channel audio signal according to whether the multi-channel audio signal exceeds a clipping threshold; the controller further configured to adjust the clipping threshold according to a supply voltage for the audio system relative to a tuning voltage, the clipping threshold being adjusted to clip channels of the multi-channel audio signal in accordance with a threshold corresponding to the tuning voltage at a time of tuning the automotive audio system; and an amplifier configured to process a gain-adjusted multi-channel audio signal, where the controller lowers the clipping threshold when the supply voltage is less than the tuning voltage.
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7. An automotive audio system comprising:
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a controller configured to control gain adjustment for each channel of a multi-channel audio signal according to whether the multi-channel audio signal exceeds a clipping threshold; the controller further configured to adjust the clipping threshold according to a supply voltage for the audio system relative to a tuning voltage, the clipping threshold being adjusted to clip channels of the multi-channel audio signal in accordance with a threshold corresponding to the tuning voltage at a time of tuning the automotive audio system; and an amplifier configured to process a gain-adjusted multi-channel audio signal, where the controller increases the clipping threshold when the supply voltage is above the tuning voltage.
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8. A method for compensating for acoustic distortion in an automotive audio system comprising:
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controlling a gain of at least one channel of a multi-channel audio signal with a controller according to whether the audio signal exceeds a clipping threshold; sensing a rail voltage with the controller; comparing the sensed rail voltage to a predetermined tuning voltage with the controller, the predetermined tuning voltage being the rail voltage at a time of tuning the automotive audio system; and adjusting the clipping threshold with the controller according to the comparison of the sensed rail voltage to the predetermined tuning voltage to maintain a substantially fixed level of distortion by clipping channels of the multi-channel audio signal at the adjusted clipping threshold corresponding to the predetermined tuning voltage. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. An automotive audio amplifier comprising:
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an acoustic signal processor configured to control gain for at least one channel of a multi-channel audio signal, the gain being controlled according to a gain adjust signal; a voltage sensor configured to generate a voltage sense signal associated with a battery supply voltage for the amplifier; and a threshold detector configured to generate the gain adjust signal according to detection that an output of a gain circuit for the at least one channel exceeds a clipping threshold, the clipping threshold being adjustable according to the voltage sense signal so that the clipping threshold maintains a substantially fixed level of distortion by clipping channels of the multi-channel audio signal at a threshold relative to the battery supply voltage, where the clipping threshold is reduced when the threshold detector detects that a voltage sensed by the voltage sense signal is less than a reference voltage corresponding to a tuning voltage at a time of tuning the automotive audio amplifier, and the gain is reduced when the threshold detector detects that the at least one channel of the multi-channel audio signal exceeds the reduced clipping threshold. - View Dependent Claims (20, 21, 22)
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Specification