Digital automatic gain control
First Claim
1. A hearing aid, comprising:
- a microphone to receive an input signal;
a speaker to reproduce the input signal; and
a processor to process the input signal at a gain, wherein the processor includes an inhibitor to inhibit distortions and an adjuster to adjust the gain of the input signal, wherein the inhibitor smoothes an envelope of the input signal so as to inhibit distortions arising from apparent modulation of the input signal.
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Accused Products
Abstract
Systems, devices, and methods are provided to inhibit apparent amplitude modulation in non-linear processing that causes distortion in a processed signal. One aspect of the invention includes a hearing aid. The hearing aid includes a microphone to receive an input signal, a speaker to reproduce the input signal, and a processor. The processor processes the input signal using a gain. The processor includes an inhibitor, which inhibits distortions, and an adjuster, which adjusts the gain. The inhibitor acts to smooth an envelope of the input signal to inhibit undesired modulation. The adjuster adjusts the gain if the envelope is either above or below a threshold.
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Citations
59 Claims
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1. A hearing aid, comprising:
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a microphone to receive an input signal;
a speaker to reproduce the input signal; and
a processor to process the input signal at a gain, wherein the processor includes an inhibitor to inhibit distortions and an adjuster to adjust the gain of the input signal, wherein the inhibitor smoothes an envelope of the input signal so as to inhibit distortions arising from apparent modulation of the input signal. - View Dependent Claims (2, 3, 4, 5)
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6. A method for providing automatic gain control, comprising:
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smoothing an envelope of an input signal having a gain; and
adjusting the gain if the envelope is one of two conditions, wherein the two conditions includes being greater than a threshold and being less than the threshold, wherein the act of smoothing inhibits distortions arising from modulation of the input signal. - View Dependent Claims (7, 8, 9, 10)
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11. A hearing aid, comprising:
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an adjuster to adjust a gain so as to amplify an input signal; and
a detector to form a smooth envelope that is a rectified version of the input signal, wherein the detector presents the smooth envelope to the adjuster, and wherein the smooth envelope excludes apparent modulation of the input signal. - View Dependent Claims (12, 13, 14, 15, 17, 18, 19, 20)
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16. A hearing aid, comprising:
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a preamplifier having a gain to amplify the input signal;
a detector to form a smooth envelope that is rectified; and
an adjuster to adjust the gain of the preamplifier if the smooth envelope is one of two conditions, wherein the two conditions includes being greater than a threshold and being less than the threshold, and wherein the smooth envelope is defined to exclude the modulation that distorts the input signal.
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21. A digital analog gain control, comprising:
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a detector to detect an envelope of an input signal using Hilbert filters;
an adder to provide a difference between the envelope and a threshold; and
an adjuster that adjust a gain if the difference is one of two conditions, wherein the two conditions includes being greater than zero and being less than zero. - View Dependent Claims (22, 23, 24, 25, 26, 27, 29, 30, 31, 32, 33, 34, 35, 37, 38, 39, 40, 41, 42)
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28. A digital analog gain control, comprising:
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a detector to detect an envelope of an input signal using Hilbert filters;
an adder to provide a difference between the envelope and a threshold; and
an adjuster that receives the difference, a release time constant, and an attack time constant, wherein the adjuster adjust a gain if the difference is one of two conditions, wherein the two conditions includes being a negative number and being a positive number, wherein the adjuster increases the gain if the difference is negative, and wherein the adjuster decreases the gain if the difference is positive.
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36. A digital analog gain control, comprising:
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a filter to block low frequencies from an input signal;
a detector to detect an envelope of the input signal using Hilbert filters;
an adder to provide a difference between the envelope and a threshold; and
an adjuster that receives the difference, a release time constant, and an attack time constant, wherein the adjuster adjust a gain if the difference is one of two conditions, wherein the two conditions includes being a negative number and being a positive number, wherein the adjuster increases the gain if the difference is negative, and wherein the adjuster decreases the gain if the difference is positive.
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43. A digital analog gain control, comprising:
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a detector to detect an envelope of the input signal using IIR filters;
an adder to provide a difference between the envelope and a threshold; and
an adjuster that receives the difference, a release time constant, and an attack time constant, wherein the adjuster adjust a gain if the difference is one of two conditions, wherein the two conditions includes being a negative number and being a positive number, wherein the adjuster increases the gain if the difference is negative, and wherein the adjuster decreases the gain if the difference is positive. - View Dependent Claims (44, 45, 46, 47, 48, 49)
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50. A method for controlling a gain of an amplifier, comprising:
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blocking low frequencies from an input signal that is digitized;
forming an envelope that lacks modulation using Hilbert filters; and
subtracting the envelope from a threshold to form a difference, wherein the difference is used to control the gain. - View Dependent Claims (51, 52, 53, 54, 55, 56, 57, 58, 59)
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Specification