Determining linear predictive coding filter parameters for encoding a voice signal
AssigneeInterDigital Technology Corporation
InventorsDaniel Lin, Brian M. McCarthy
Life of this patent
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Abstract
Linear predictive coding (LPC) filter parameters are determined for use in encoding a voice signal. Samples of a speech signal using a z-transform function are pre-emphasized. The pre-emphasized samples are analyzed to produce LPC reflection coefficients. The LPC reflection coefficients are quantized by a voiced quantizer and by an unvoiced quantizer producing sets of quantized reflection coefficients. Each set is converted into respective spectral coefficients. The set which produces a smaller lag-spectral distance is determined. The determined set is selected to encode the voice signal.
Claims8
A method for determining linear predictive coding (LPC) filter parameters for use in encoding a voice signal, the method comprising:
- pre-emphasizing samples of a speech signal using a z-transform function;
- analyzing the pre-emphasized samples to produce LPC reflection coefficients;
- quantizing the LPC reflection coefficients by a voiced quantizer and by an unvoiced quantizer producing sets of quantized reflection coefficients;
- converting each set into respective coefficients;
- determining the set which produces a smaller log-spectral distance based on in part that set's respective spectral coefficients;
- and
- selecting the determined set to encode the voice signal.
An apparatus for determining linear predictive coding (LPC) filter parameters for use in encoding a voice signal, the apparatus comprising:
- a pre-emphasis block for pre-emphasizing samples of a speech signal using a z-transform function;
- a LPC analysis block for analyzing the pre-emphasized samples to produce LPC reflection coefficients;
- and
- a reflection coefficient quantization and LPC conversion block for quantizing the LPC reflection coefficients by a voiced quantizer and by an unvoiced quantizer producing sets of quantized reflection coefficients, for converting each set into respective spectral coefficients, for determining the set which produces a smaller log-spectral distance based on in part that set's respective spectral coefficients, and for selecting the determined set to encode the voice signal.
An apparatus for determining linear predictive coding (LPC) filter parameters for use in encoding a voice signal, the apparatus comprising:
- means for pre-emphasizing samples of a speech signal using a z-transform function;
- means for analyzing the pre-emphasized samples to produce LPC reflection coefficients;
- means for quantizing the LPC reflection coefficients by a voiced quantizer and by an unvoiced quantizer producing sets of quantized reflection coefficients;
- means for converting each set into respective spectral coefficients;
- means for determining the set which produces a smaller log-spectral distance based on in part that set's respective spectral coefficients;
- and
- means for selecting the determined set to encode the voice signal.
Dependencies are inferred from the claim text.