| 摘要 |
PROBLEM TO BE SOLVED: To provide a band extending device for improving acoustic tone quality by extending the frequency band of signals by a relatively small operation amount for the input signals of a narrow band. SOLUTION: This device comprises: a spectrum parameter calculation circuit 100 which calculates a spectrum parameter for the input signals x(n) of the narrow band; a coefficient calculation circuit 130 which inputs the spectrum parameter and converts it to the coefficient of band-extended signals; a noise generation circuit 120 which generates and outputs band-limited noise signals; a gain circuit 140 which inputs gain from a gain adjusting circuit 210, multiplies the output signals of the noise generation circuit 120 with the gain and outputs them to a composite filter circuit 170; the composite filter circuit 170 which inputs the coefficient from the coefficient calculation circuit 130, constitutes a filter, passes the signals of the gain circuit 140 through the filter and outputs high band signals y(n) for band extension; a sampling frequency conversion circuit 180 which inputs the signals x(n) and outputs the signals s(n) up-sampled to a predetermined sampling frequency; and an adder 190 which adds the respective output signals of the composite filter circuit 170 and the sampling frequency conversion circuit 180 and outputs the band-extended signals. COPYRIGHT: (C)2004,JPO
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