| 摘要 |
A bandwidth expanding device comprising a spectrum parameter calculating circuit (100) for calculating a spectrum parameter of a narrow-bandwidth inp ut signal x(n), a coefficient calculating circuit (130) for receiving the spectrum parameter and converting it into the coefficient of a signal the bandwidth of which is expanded, a gain circuit (140) for receiving a gain fr om a gain control circuit (210), multiplying the output signal from a noise generating circuit (120) and the gain, and outputting the product to a combined filter circuit (170), the combined filter circuit (170) for receivi ng the coefficient from coefficient calculating circuit (130) to constitute a filter and passing the signal from the gain circuit (140) through the filter to output a high-frequency signal y(n) for bandwidth expansion, a sampling frequency converting circuit (180) for receiving the narrow-bandwidth input signal x(n) and outputting a signal s(n) the frequency of which is up-sample d to a predetermined sampling frequency, and an adder (190) for adding the hig h- pass signal y(n) to the signal s(n) and outputting an expanded bandwidth signal.
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