Controlling a weighting filter based on the spectral content of a speech signal
First Claim
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1. A method for preparing a speech signal for encoding, the method comprising:
- providing a pitch pre-processing weighting filter including a core weighting filter component and a low-pass filter;
providing a fixed-codebook weighting filter including the core weighting filter component and a high-pass filter;
providing an adaptive-codebook weighting filter including the core weighting filter component;
determining whether a spectral content of the speech signal is representative of a defined spectral characteristic;
controlling said low-pass filter and said high-pass filter based on a determination of the spectral content of the speech signal.
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Abstract
A method for preparing a speech signal for encoding comprises determining whether the spectral content of an input speech signal is representative of a defined spectral characteristic (e.g., a defined characteristic slope). A frequency specific filter component of a weighting filter is controlled based on the determination of the spectral content of the speech signal or/and its location in the encoder. A core weighting filter component of the weighting filter may be maintained regardless of the spectral content of the speech signal.
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Citations
29 Claims
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1. A method for preparing a speech signal for encoding, the method comprising:
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providing a pitch pre-processing weighting filter including a core weighting filter component and a low-pass filter; providing a fixed-codebook weighting filter including the core weighting filter component and a high-pass filter; providing an adaptive-codebook weighting filter including the core weighting filter component; determining whether a spectral content of the speech signal is representative of a defined spectral characteristic; controlling said low-pass filter and said high-pass filter based on a determination of the spectral content of the speech signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. An encoder for encoding a speech signal, the encoder comprising:
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a pitch pre-processing weighting filter including a core weighting filter component and a low-pass filter; a fixed-codebook weighting filter including the core weighting filter component and a high-pass filter; an adaptive-codebook weighting filter the core weighting filter component; a spectral detector for determining whether a spectral content of the speech signal is representative of a defined spectral characteristic; a controller adapted to control said low-pass filter and said high-pass filter based on a determination of the spectral content of the speech signal. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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Specification