Speech coding system with time-domain noise attenuation
First Claim
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1. A speech coding system comprising:
- a preprocessor configured to receive a digitized signal from an analog-to-digital converter in time-domain, the preprocessor configured to transform the digital signal into frequency-domain, modify spectral magnitudes of the digitized signal in frequency-domain to generate a noise-reduced digitized signal and transform the noise-reduced digitized signal back to time-domain;
an encoder disposed to receive the noise-reduced digitized signal in time-domain, the encoder to provide a bitstream based upon a speech coding of the noise-reduced digitized signal;
where the speech coding determines at least one gain scaling a portion of the noise-reduced digitized signal; and
where the encoder adjusts the at least one gain as a function of noise characteristic for attenuating background noise in at least one frame,wherein the at least one gain is adjusted according to a gain factor, the gain factor facilitating time-domain background noise attenuation.
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Abstract
A speech coding system is provided with time-domain noise attenuation. The speech coding system has an encoder operatively connected to a decoder via a communication medium. A preprocessor processes a digitized speech signal from an analog-to-digital converter. Speech coding systems are used to encode and decode a bitstream. Gains from the speech coding are adjusted by a gain factor Gf that provides time-domain background noise attenuation.
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Citations
68 Claims
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1. A speech coding system comprising:
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a preprocessor configured to receive a digitized signal from an analog-to-digital converter in time-domain, the preprocessor configured to transform the digital signal into frequency-domain, modify spectral magnitudes of the digitized signal in frequency-domain to generate a noise-reduced digitized signal and transform the noise-reduced digitized signal back to time-domain; an encoder disposed to receive the noise-reduced digitized signal in time-domain, the encoder to provide a bitstream based upon a speech coding of the noise-reduced digitized signal; where the speech coding determines at least one gain scaling a portion of the noise-reduced digitized signal; and where the encoder adjusts the at least one gain as a function of noise characteristic for attenuating background noise in at least one frame, wherein the at least one gain is adjusted according to a gain factor, the gain factor facilitating time-domain background noise attenuation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A speech coding system comprising:
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a decoder disposed to receive a bitstream, the decoder to provide a reconstructed signal based upon a speech decoding of the bitstream; where the speech decoding determines at least one gain scaling a portion of the reconstructed signal wherein the decoder adjusts the at least one gain as a function of noise characteristic for attenuating background noise in at least one frame and generating a background noise attenuated signal, and wherein the at least one gain is adjusted according to a gain factor, the gain factor facilitating time-domain background noise attenuation; and a postprocessor configured to receive the background noise attenuated signal in time-domain, the postprocessor configured to transform the background noise attenuated signal into frequency-domain, modify spectral magnitudes of the background noise attenuated signal in frequency-domain to generate a noise-reduced attenuated signal and transform the noise-reduced attenuated signal back to time-domain. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A speech coding system comprising:
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a preprocessor configured to receive a digitized signal from an analog-to-digital converter in time-domain, the preprocessor configured to transform the digital signal into frequency-domain, modify spectral magnitudes of the digitized signal in frequency-domain to generate a noise-reduced digitized signal and transform the noise-reduced digitized signal back to time-domain; an encoder disposed to receive a the noise-reduced digitized signal, the encoder to provide a bitstream based upon a speech coding of the noise-reduced digitized signal, where the speech coding determines at least one gain scaling a portion of the digitized signal, and where the encoder adjusts the at least one gain as a function of noise characteristic; and a decoder operatively connected to receive the bitstream from the encoder, where the decoder provides a reconstructed signal based upon a speech decoding of the bitstream, where the speech decoding reconstructs the at least one gain scaling the portion of the digitized signal, and where the decoder adjusts the at least one gain as a function of noise characteristic for attenuating background noise in at least one frame and generating a background noise attenuated signal, wherein the at least one gain is adjusted according to a gain factor, the gain factor facilitating time-domain background noise attenuation. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43)
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44. A method of speech coding comprising:
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receiving a digitized signal in time-domain; transforming the digital signal into frequency-domain; modifying spectral magnitudes of the digitized signal in frequency-domain to generate a noise-reduced digitized signal; transforming the noise-reduced digitized signal back to time-domain; segmenting the noise-reduced digitized signal into at least one portion; determining at least one gain scaling the noise-reduced digitized signal within the one portion; adjusting the at least one gain as a function of noise characteristic; and quantizing the at least one gain into a group of at least one bit for a bitstream, where the at least one gain is adjusted as a function of noise characteristic for attenuating background noise in at least one frame, wherein the at least one gain is adjusted according to a gain factor, the gain factor facilitating time-domain background noise attenuation. - View Dependent Claims (45, 46, 47, 48, 49, 50, 51, 52)
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53. A method of speech coding comprising:
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decoding at least one gain from a group of at least one bit in a bitstream; adjusting the at least one gain as a function of noise characteristic; assembling the at least one gain into a portion of a reconstructed speech signal, where the at least one gain is adjusted as a function of noise characteristic for attenuating background noise in at least one frame and generating a background noise attenuated signal in time-domain, and wherein the at least one gain is adjusted according to a gain factor, the gain factor facilitating time-domain background noise attenuation; transforming the background noise attenuated signal into frequency-domain; modifying spectral magnitudes of the background noise attenuated signal in frequency-domain to generate a noise-reduced attenuated signal; and transforming the noise-reduced attenuated signal back to time-domain. - View Dependent Claims (54, 55, 56, 57, 58, 59, 60)
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61. A method of speech coding comprising:
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receiving a digitized signal in time-domain; transforming the digital signal into frequency-domain; modifying spectral magnitudes of the digitized signal in frequency-domain to generate a noise-reduced digitized signal; transforming the noise-reduced digitized signal back to time-domain; segmenting the noise-reduced digitized signal into at least one portion; determining at least one gain representing the noise-reduced digitized signal within the one portion; pre-adjusting the at least one gain as a function of noise characteristic; quantizing the at least one gain into a group of at least one bit for a bitstream. decoding the at least one gain from the group of at least one bit in the bitstream; post-adjusting the at least one gain as a function of noise characteristic; and assembling the at least one gain into a reconstructed speech signal, where the at least one gain is adjusted as a function of noise characteristic for attenuating background noise in at least one frame, wherein the at least one gain is adjusted according to a gain factor, the gain factor facilitating time-domain background noise attenuation. - View Dependent Claims (62, 63, 64, 65, 66, 67, 68)
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Specification