Voice decoder, voice decoding method and program for decoding voice signals
First Claim
1. A voice decoder comprising:
- a first voice decoding circuit which is specialized for decoding at least one encoded narrow band voice signal;
a second voice decoding circuit which is specialized for decoding at least one encoded wide band voice signal; and
a band determination circuit which determines whether a target signal to be decoded is a narrow band voice signal or a wide band voice signal, and wherein;
said band determination circuit supplies said first voice decoding circuit with the target signal in a case where it is determined that the target signal is a narrow band voice signal, and supplies said second voice decoding circuit with the target signal in a case where it is determined that the target signal is a wide band voice signal;
said first voice decoding circuit decodes the target signal supplied from said band determination circuit; and
said second voice decoding circuit decodes the target signal supplied from said band determination circuit.
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Abstract
A voice decoder comprises the first voice decoding circuit which is specialized for decoding narrow band voice signal, the second voice decoding circuit which is specialized for decoding wide band voice signals, and a band determination circuit which determines whether a target signal to be decoded is a narrow band voice signal or wide band voice signal. The band determination circuit supplies the first voice decoding circuit with the target signal in a case where it is determined that the target signal is a narrow band voice signal, and supplies the second voice decoding circuit with the target signal in a case where it is determined that the target signal is a wide band voice signal. The first voiced decoding circuit decodes the supplied target signal. The second voice decoding circuit decodes the supplied target signal.
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Citations
9 Claims
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1. A voice decoder comprising:
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a first voice decoding circuit which is specialized for decoding at least one encoded narrow band voice signal;
a second voice decoding circuit which is specialized for decoding at least one encoded wide band voice signal; and
a band determination circuit which determines whether a target signal to be decoded is a narrow band voice signal or a wide band voice signal, and wherein;
said band determination circuit supplies said first voice decoding circuit with the target signal in a case where it is determined that the target signal is a narrow band voice signal, and supplies said second voice decoding circuit with the target signal in a case where it is determined that the target signal is a wide band voice signal;
said first voice decoding circuit decodes the target signal supplied from said band determination circuit; and
said second voice decoding circuit decodes the target signal supplied from said band determination circuit. - View Dependent Claims (2)
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3. A voice decoder comprising:
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an LSP generation circuit which generates at least one LSP from an encoded narrow band voice signal or wide band voice signal as a target signal to be decoded;
an converter which converts the at least one LSP into at least one LPC (Linear Prediction Code);
an excitation signal generator which generates an excitation signal for use in linear prediction synthesis, from the target signal; and
a voice signal generator which generates a narrow band voice signal or wide band voice signal by performing linear prediction synthesis using the at least one LPC and the excitation signal, and wherein;
said converter comprises a first conversion circuit which converts the at least one LSP into the at least one LPC with an adequate level of calculation accuracy for decoding narrow band voice signals, a second conversion circuit which converts the at least one LSP into the at least one LPC with an adequate level of calculation accuracy for decoding wide band voice signals, and a first supply circuit which determines whether the target signal is a narrow band voice signal or wide band voice signal by determining whether number of the at least one LSP is equal to or larger than a predetermined number, supplies said first conversion circuit with the at least one LSP in a case where it is determined that the target signal is a narrow band voice signal, and supplies said second conversion circuit with the at least one LSP in a case where it is determined that the target signal is a wide band voice signal; and
said voice signal generator comprises a first synthesis filter which performs linear prediction synthesis using the at least one LPC generated by said first conversion circuit and the excitation signal, with an adequate level of calculation accuracy for decoding narrow band voice signals, a second synthesis filter which performs linear prediction synthesis using the at least one LPC generated by said second conversion circuit and the excitation signal, with an adequate level of calculation accuracy for decoding wide band voice signals, and a second supply circuit which determines whether the target signal is a narrow band voice signal or wide band voice signal by determining whether number of the at least one LSP is equal to or larger than a predetermined number, supplies said first synthesis filter with the excitation signal in a case where it is determined that the target signal is a narrow band voice signal, and supplies said second synthesis filter with the excitation signal in a case where it is determined that the target signal is a wide band voice signal. - View Dependent Claims (4)
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5. A voice decoder comprising:
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an LSP generation circuit which generates at least one LSP from an encoded narrow band voice signal or wide band voice signal as a target signal to be decoded;
a converter which converts the at least one LSP into at least one LPC;
an excitation signal generator which generates an excitation signal for use in performing linear predication synthesis from the target signal; and
a voice signal generator which generates a narrow band voice signal or wide band voice signal, by performing linear prediction synthesis using the at least one LPC and the excitation signal, and wherein said voice signal generator includes a first synthesis filter which performs linear prediction synthesis using the at least one LPC and excitation signal, with an adequate level of calculation accuracy for decoding narrow band voice signals, a second synthesis filter which performs linear prediction synthesis using the at least one LPC and excitation signal, with an adequate level of calculation accuracy for decoding wide band voice signals;
a first supply circuit which determines whether the target signal is a narrow band voice signal or wide band voice signal by determining whether number of the at least one LPC is equal to or larger than a predetermined number, supplies said first synthesis filter with the at least one LPC in a case where it is determined that the target signal is a narrow band voice signal, and supplies said second synthesis filter with the at least one LPC in a case where it is determined that the target signal is a wide band voice signal, and a second supply circuit which determines whether the target signal is a narrow band voice signal or wide band voice signal by determining whether number of the at least one LSP is equal to or larger than a predetermined number, supplies said first synthesis filter with the excitation signal in a case where it is determined that the target signal is a narrow band voice signal, and supplies said second filter with the excitation signal in a case where it is determined that the target signal is a wide band voice signal. - View Dependent Claims (6)
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7. A voice decoding method comprising:
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determining whether a target signal to be decoded is a narrow band voice signal or wide band voice signal;
decoding the target signal with an adequate level of calculation accuracy for decoding narrow band voice signals, in a case where it is determined that the target signal is a narrow band voice signal; and
decoding the target signal with an adequate level of calculation accuracy for decoding wide band voice signals, in a case where it is determined that the target signal is wide band voice signal. - View Dependent Claims (8)
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9. A program for controlling a computer to function as a voice decoder comprising:
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a first voice decoding circuit which is specialized for decoding at least one encoded arrow band voice signal;
a second voice decoding circuit which is specialized for decoding at least one encoded wide band voice signal; and
a band determination circuit which determines whether a target signal to be decoded is a narrow band voice signal or wide band voice signal, and wherein said band determination circuit supplies said first voice decoding circuit with the target signal in a case where it is determined that the target signal is a narrow band voice signal, and supplies said second voice decoding circuit with the target signal in a case where it is determined that the target signal is a wide band voice signal, said first voice decoding circuit decodes the target signal supplied from said band determination circuit, and said second voice decoding circuit decodes the target signal supplied from said band determination circuit.
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Specification