| 摘要 |
A band extending apparatus includes a spectral parameter calculating circuit (100) for calculating spectral parameters of a narrow-band input signal x(n), a coefficient calculating circuit (130) supplied with the spectral parameters to convert the spectral parameters into coefficients of a band extended signal, and a gain circuit (140) supplied with a gain from a gain adjustment circuit (210) and multiplying an output signal of a noise generating circuit (120) with the gain to output the resulting signal to a synthesis filter circuit (170). The synthesis filter circuit (170) forms a filter by receiving coefficients from the coefficient calculating circuit (130). The signal from the gain circuit (140) is passed through the filter. The synthesis filter circuit outputs a high band signal y(n) for band extension. The band extending apparatus also includes a sampling frequency converting circuit (180), supplied with the narrow-band input signal x(n) to output a signal s(n) up-sampled to a preset sampling frequency, and an adder (190) for summing the high band signal y(n) to the up sampled signal s(n) to output a band extended signal. <IMAGE>
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