Speech coding apparatus having amplitude information set to correspond with position information
First Claim
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1. A speech coding apparatus for calculating a spectral parameter from a speech signal inputted thereto, quantizing an excitation signal of the speech signal using the spectral parameter and outputting the quantized excitation signal, comprising:
- an excitation quantization section for quantizing the excitation signal using a plurality of pulses, each pulse being defined by a position and an amplitude,wherein a position of at least one pulse is determined from N possible position variations of said at least one pulse, N being set in advance to be greater than one, andwherein an amplitude value is set in advance for each of said N possible position variations of said at least one pulse and an amplitude of said at least one pulse is determined as the amplitude value corresponding to the determined position of the said at least one pulse.
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Abstract
The invention provides a speech coding apparatus by which a good sound quality can be obtained even when the bit rate is low. The speech coding apparatus includes an excitation quantization circuit which quantizes an excitation signal using a plurality of pulses. The position of at least one of the pulses is represented by a number of bits determined in advance, and the amplitude of the pulse is determined in advance depending upon the position of the pulse.
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Citations
20 Claims
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1. A speech coding apparatus for calculating a spectral parameter from a speech signal inputted thereto, quantizing an excitation signal of the speech signal using the spectral parameter and outputting the quantized excitation signal, comprising:
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an excitation quantization section for quantizing the excitation signal using a plurality of pulses, each pulse being defined by a position and an amplitude, wherein a position of at least one pulse is determined from N possible position variations of said at least one pulse, N being set in advance to be greater than one, and wherein an amplitude value is set in advance for each of said N possible position variations of said at least one pulse and an amplitude of said at least one pulse is determined as the amplitude value corresponding to the determined position of the said at least one pulse. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A speech coding apparatus for calculating a spectral parameter from a speech signal inputted thereto, quantizing an excitation signal of the speech signal using the spectral parameter and outputting the quantized excitation signal, comprising:
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an excitation quantization section for quantizing the excitation signal using a plurality of pulses, each pulse being defined by a position and an amplitude, wherein a position of at least one pulse is determined from N possible position variations of said at least one pulse, N being set in advance to be greater than one, and wherein an amplitude or polarity of the at least one pulse is quantized simultaneously with amplitudes and polarities of the remaining plurality of pulses. - View Dependent Claims (9, 10, 11)
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12. A speech coding apparatus for calculating a spectral parameter from a speech signal inputted thereto, quantizing an excitation signal of the speech signal using the spectral parameter and outputting the quantized excitation signal, comprising:
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a mode discrimination section for discriminating a mode from the speech signal inputted thereto and outputting discrimination information; and an excitation quantization section for quantizing the excitation signal using a plurality of pulses, each pulse being defined by a position and an amplitude, when the discrimination information from said mode discrimination section represents a specific mode, wherein a position of at least one pulse is determined from N possible position variations of said at least one pulse, N being set in advance to be greater than one, and wherein an amplitude value is set in advance for each of the N possible position variations of said at least one pulse and an amplitude of said at least one pulse is determined as the amplitude value corresponding to the determined position of said at least one pulse. - View Dependent Claims (13, 14, 15)
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16. A speech coding apparatus for calculating a spectral parameter from a speech signal inputted thereto, quantizing an excitation signal of the speech signal using the spectral parameter and outputting the quantized excitation signal, comprising:
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a mode discrimination section for discriminating a mode from the speech signal inputted thereto and outputting discrimination information; and an excitation quantization section for quantizing the excitation signal using a plurality of pulses, each pulse being defined by a position and an amplitude, when the discrimination information from said mode discrimination section represents a specific mode, wherein a position of at least one pulse is determined from N possible position variations of the pulse, N being set in advance to be greater than one, and wherein an amplitude or polarity of the at least one pulse is quantized simultaneously with amplitudes and polarities of the remaining plurality of pulses. - View Dependent Claims (17, 18, 19, 20)
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Specification