Embedded code-excited linerar prediction speech coding and decoding apparatus and method
First Claim
1. A speech coding apparatus comprising:
- a core speech coding unit which presents a speech signal with spectral envelop and an excitation signal;
a transmission rate determination unit which allocates the number of bits that are additionally allowed depending on a capacity of a transmission channel; and
an embedded excitation signal coding unit for coding a residual excitation signal that is not coded in the core speech coding unit based on the number of additionally allowed bits by using one of a multiple pulse excitation coding method and a gain compensation method.
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Abstract
Provides is an embedded code-excited linear prediction speech coding/decoding apparatus and method that can deal with the capacity change of speech transmission channel by modeling an error signal not coded at a core speech coder based on a transmission rate in a multiple pulse search mode- or gain compensation mode and then transmitting it in an optimum mode. The apparatus includes a core speech coding unit for coding an input speech signal with spectral envelop and an excitation signal, a transmission rate determination unit for allocating the number of bits additionally allowed depending on a capacity of a transmission channel, and an embedded excitation signal coding unit for coding a residual excitation signal that is not coded in the core speech coding unit based on the number of additionally allowed bits using one of a multiple pulse excitation coding mode and a gain compensation mode.
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Citations
19 Claims
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1. A speech coding apparatus comprising:
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a core speech coding unit which presents a speech signal with spectral envelop and an excitation signal;
a transmission rate determination unit which allocates the number of bits that are additionally allowed depending on a capacity of a transmission channel; and
an embedded excitation signal coding unit for coding a residual excitation signal that is not coded in the core speech coding unit based on the number of additionally allowed bits by using one of a multiple pulse excitation coding method and a gain compensation method. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A speech decoding apparatus comprising:
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an excitation signal reproduction unit which reconstructs a basic excitation signal using adaptive codebook index and gain, and an algebraic codebook index and gain of core speech coder;
an embedded excitation signal reproduction unit for decoding an excitation signal from a bit stream added in an embedded type; and
a linear prediction synthesis filter unit which reconstructs a speech signal by performing a linear prediction synthesis of the decoded excitation signals at the excitation signal reproduction unit and at the embedded excitation signal reproduction unit. - View Dependent Claims (8, 9)
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10. A speech coding method comprising the steps of:
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a) coding a speech signal using a conventional speech coder; and
b) coding a residual excitation signal which is not coded via the conventional speech coder based on a channel transmission rate using one of a multiple pulse excitation coding mode and a gain compensation mode. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A speech decoding method comprising the steps of:
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a) decoding a basic excitation signal using an adaptive codebook index and gain, and an algebraic codebook index and gain;
b) decoding an excitation signal from a bit stream added in an embedded type; and
c) reconstructing a speech signal by performing a linear prediction synthesis filter of the excitation signals decoded at said steps a) and b). - View Dependent Claims (18, 19)
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Specification