Signal processing circuit and method for increasing speech intelligibility
First Claim
1. A method of processing an audio signal in a hearing aid for increasing speech intelligibility to a human, comprising:
- receiving an audio signal;
differentially amplifying a first frequency range that substantially comprises first speech formant frequencies and a second frequency range that substantially comprises second formant frequencies of the audio signal;
mixing an injected inaudible signal tone with the audio signal;
sensing a level of presence of the signal tone; and
automatically controlling gain amplification of only the second frequency range based on the sensed level of the signal tone;
the controlling the gain amplification based on the sensed level to substantially prevent regenerative oscillation of the audio signal and to amplify the second formant frequencies without creating howling.
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Accused Products
Abstract
A signal processing circuit and method for increasing speech intelligibility. The invention comprises a receiving circuit for receiving an audio signal detectable by a human. A gain amplifying circuit provides gain amplification of the audio signal. A shaping filter modifies the audio signal to be in phase with a second audio signal present at the receiving circuit and which is detected by the human unprocessed by the signal processing circuit. The shaping filter further differentially amplifies first and second speech formant frequencies to restore a normal loudness relationship between them. A feedback circuit controls the gain amplification in the gain amplifying circuit for enabling the signal processing circuit to substantially prevent regenerative oscillation of the amplified audio signal. Additionally, a signal tone may be injected into the signal processing circuit for automatically controlling the gain amplifying circuit.
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Citations
22 Claims
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1. A method of processing an audio signal in a hearing aid for increasing speech intelligibility to a human, comprising:
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receiving an audio signal;
differentially amplifying a first frequency range that substantially comprises first speech formant frequencies and a second frequency range that substantially comprises second formant frequencies of the audio signal;
mixing an injected inaudible signal tone with the audio signal;
sensing a level of presence of the signal tone; and
automatically controlling gain amplification of only the second frequency range based on the sensed level of the signal tone;
the controlling the gain amplification based on the sensed level to substantially prevent regenerative oscillation of the audio signal and to amplify the second formant frequencies without creating howling. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of processing an audio signal in a hearing aid to increase speech intelligibility to a human, comprising:
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receiving an audio signal;
passing the audio signal through a signal processing circuit having an output, and outputting a modified audio signal from the output;
phase aligning the modified audio signal with an unpassed audio signal present at the output;
amplifying frequencies of the audio signal differentially to amplify a second frequency range comprising second speech formant frequencies of the audio signal with an amplified gain that is greater than a gain amplification of a first frequency range comprising first speech formant frequencies; and
controlling the amplified gain based on an inaudible signal tone;
the controlling the amplified gain based on the inaudible signal tone to effect the amplified gain regardless of a presence of noise in the first and second frequency ranges and to substantially prevent regenerative oscillation the amplified audio signal. - View Dependent Claims (15, 16, 17, 18)
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19. A hearing aid signal processing circuit to increase speech intelligibility to a human, the human having at least one eardrum, comprising:
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a receiving circuit to receive an audio signal;
a gain amplifying circuit to differentially amplify a first frequency range comprising first speech formant frequencies and a second frequency range comprising second speech formant frequencies of the audio signal as a function of a difference in dedibels to restore a sound pressure level of the second frequency range to a normal level dependent on the human and a frequency of the audio signal; and
a feedback circuit to control gain amplification of only one of the frequency ranges based on a sensed level of an inaudible continuous signal tone;
the feedback circuit'"'"'s control of the gain amplification based on the sensed level of the inaudible signal tone to substantially prevent regenerative oscillation of the audio signal. - View Dependent Claims (20, 21, 22)
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Specification