Signal bandwidth extension apparatus

1. A signal band extension apparatus, which extends a band of an input signal, the apparatus comprising:

a wideband processing module configured to extend a band of the input signal;

a determination module configured to determine whether or not an input signal whose band has been extended by the wideband processing module comprises a peak component greater than a predetermined threshold in the extended band; and

a controller configured to extend the band of the input signal by using the input signal whose band has been extended by the wideband processing module when the determination module determines that the input signal comprises the peak component, and not to perform an extension of the band of the input signal by using the input signal whose band has been extended by the wideband processing module when the determination module determines that the input signal does not comprise the peak component.

2. The apparatus of claim 1 , wherein the wideband processing module comprises:

an analysis module configured to analyze the input signal to obtain a narrow band spectrum parameter and a narrow band excitation signal; and

a band extension module configured to extend a band of the narrow band excitation signal obtained by the analysis module based on a predetermined non-linear function,

wherein the determination module is configured to determine whether or not the narrow band excitation signal extended by the band extension module comprises a peak component greater than a predetermined threshold in the extended band, and

wherein the controller is configured to extend the band of the input signal based on a determination result by the determination module and a comparison result of an input signal and output signal of the band extension module.

3. The apparatus of claim 2 , further comprising:

a synthesis module configured to synthesize a band extended narrowband excitation signal with the narrowband spectral parameter to generate a wideband signal,

wherein the controller is configured to execute a dip emphasizing process to emphasize a dip of the wideband signal when a band is to be extended, and not to execute the dip emphasizing process when a band is not to be extended.

4. The apparatus of claim 2 , wherein the controller is configured to (i) when a band is to be extended, synthesize a band extended narrowband excitation signal with the narrowband spectral parameter, execute a filter processing on a synthesized signal, add a filtered signal to the input signal, and output an added signal, and (ii) when a band is not to be extended, execute a filter processing on a band extended narrowband excitation signal, add a filtered signal to the input signal, and output an added signal.

5. The apparatus of claim 2 , wherein the controller is configured to (i) when a band is to be extended, synthesize a band extended narrowband excitation signal with the narrowband spectral parameter, execute a filter processing on a synthesized signal, add a filtered signal to the input signal, and output an added signal, and (ii) when a band is not to be extended, synthesize a silent signal with the narrowband spectral parameter, execute a filter processing on a synthesized signal, add a filtered signal to the input signal, and output an added signal.

6. The apparatus of claim 2 , wherein the controller is configured to synthesize a band extended narrowband excitation signal with the narrowband spectral parameter, extract a component of a band to be extended, add an extracted component to the input signal, and output an added signal, when a band is to be extended.

7. The apparatus of claim 2 , wherein the controller is configured to extend a low-frequency component when a band is to be extended, and not to extend the low-frequency component when a band is not to be extended.

8. The apparatus of claim 7 , wherein the controller comprises a high-frequency component extension module configured to subject the narrowband excitation signal to a band-pass filtering and extend a high-frequency component of a filtered signal when a low-frequency component is to be extended, and to extend a high-frequency component of the narrowband excitation signal without being subjected to the band-pass filtering when the low-frequency component is not to be extended.

9. The apparatus of claim 7 , wherein the controller comprises a high-frequency component extension module configured to subject the narrowband excitation signal to a first band-pass filtering and extend a high-frequency component of a filtered signal when a low-frequency component is to be extended, and to subject the narrowband excitation signal to a second band-pass filtering with a lowest pass frequency lower than a lowest pass frequency of the first band-pass filtering and extend a high-frequency component of a filtered signal when a low-frequency component is not to be extended.

10. The apparatus of claim 1 , wherein the peak component determined by the determination module comprises a fundamental frequency of the input signal.

11. The apparatus of claim 1 , wherein the controller is configured to perform a spectrum correction, and a degree of the spectrum correction to be performed for a band to be extended when a band is to be extended is stronger than a degree of the spectrum correction to be performed when a band is not to be extended.

12. The apparatus of claim 1 , wherein the controller comprises a noise suppression module configured to perform a noise suppression, and a degree of the noise suppression to be performed for a low-frequency component when a band is to be extended is weaker than a degree of the noise suppression to be performed when a band is not to be extended.

13. The apparatus of claim 1 , wherein the controller comprises a peak emphasis module configured to emphasize, when a band is to be extended, a peak of a low-frequency component with respect to an input signal of a next frame to be stronger than when a band is not to be extended.

14. A signal band extension apparatus, which extends a band of an input signal, the apparatus comprising:

a peak extraction module configured to extract at least two different peak frequencies from the input signal;

a determination module configured to determine whether or not a peak component of the input signal is lacking from the band to be extended based on a difference between the at least two peak frequencies extracted by the peak extraction module, the band to be extended being lower than the at least two peak frequencies; and

a controller configured to extend the band of the input signal when the determination module determines that the peak component is lacking, and not to extend the band of the input signal when the determination module determines that the peak component is not lacking.

15. The apparatus of claim 14 , wherein the peak extraction module comprises:

an analysis module configured to analyze the input signal to obtain a narrow band spectrum parameter and a narrow band excitation signal; and

an extractor configured to extract at least two different peak frequencies from the narrow band excitation signal obtained by the analysis module,

wherein the determination module is configured to determine whether or not the peak component of the input signal is lacking from the band to be extended based on a difference between the at least two peak frequencies extracted by the extractor.

16. The apparatus of claim 15 , further comprising:

a synthesis module configured to synthesize a band extended narrowband excitation signal with the narrowband spectral parameter to generate a wideband signal,

wherein the controller is configured to execute a dip emphasizing process to emphasize a dip of the wideband signal when a band is to be extended, and not to execute the dip emphasizing process when a band is not to be extended.

17. The apparatus of claim 15 , wherein the controller is configured to (i) when a band is to be extended, synthesize a band extended narrowband excitation signal with the narrowband spectral parameter, execute a filter processing on a synthesized signal, add a filtered signal to the input signal, and output an added signal, and (ii) when a band is not to be extended, execute a filter processing on a band extended narrowband excitation signal, add a filtered signal to the input signal, and output an added signal.

18. The apparatus of claim 15 , wherein the controller is configured to (i) when a band is to be extended, synthesize a band extended narrowband excitation signal with the narrowband spectral parameter, execute a filter processing on a synthesized signal, add a filtered signal to the input signal, and output an added signal, and (ii) when a band is not to be extended, synthesize a silent signal with the narrowband spectral parameter, execute a filter processing on a synthesized signal, add a filtered signal to the input signal, and output an added signal.

19. The apparatus of claim 15 , wherein the controller is configured to synthesize a band extended narrowband excitation signal with the narrowband spectral parameter, extract a component of a band to be extended, add an extracted component to the input signal, and output an added signal, when a band is to be extended.

20. The apparatus of claim 15 , wherein the controller is configured to extend a low-frequency component when a band is to be extended, and not to extend the low-frequency component when a band is not to be extended.

21. The apparatus of claim 20 , wherein the controller comprises a high-frequency component extension module configured to subject the narrowband excitation signal to a band-pass filtering and extend a high-frequency component of a filtered signal when a low-frequency component is to be extended, and to extend a high-frequency component of the narrowband excitation signal without being subjected to the band-pass filtering when the low-frequency component is not to be extended.

22. The apparatus of claim 20 , wherein the controller comprises a high-frequency component extension module configured to subject the narrowband excitation signal to a first band-pass filtering and extend a high-frequency component of a filtered signal when a low-frequency component is to be extended, and to subject the narrowband excitation signal to a second band-pass filtering with a lowest pass frequency lower than a lowest pass frequency of the first band-pass filtering and extend a high-frequency component of a filtered signal, when a low-frequency component is not to be extended.

23. The apparatus of claim 14 , wherein the peak component determined by the determination module comprises a fundamental frequency of the input signal.

24. The apparatus of claim 14 , wherein the controller is configured to perform a spectrum correction, and a degree of the spectrum correction to be performed for a band to be extended when a band is to be extended is stronger than a degree of the spectrum correction to be performed when a band is not to be extended.

25. The apparatus of claim 14 , wherein the controller comprises a noise suppression module configured to perform a noise suppression, and a degree of the noise suppression to be performed for a low-frequency component when a band is to be extended is weaker than a degree of the noise suppression to be performed when a band is not to be extended.

26. The apparatus of claim 14 , wherein the controller comprises a peak emphasis module configured to emphasize, when a band is to be extended, a peak of a low-frequency component with respect to an input signal of a next frame to be stronger than when a band is not to be extended.