摘要 |
A higher harmonic wave generator generates a higher harmonic wave of an inputted audio signal having a predetermined band based on the inputted audio signal. Next, a multiplier modulates an amplitude of a generated higher harmonic wave of the audio signal according to a band signal having a predetermined bandwidth so as to generate an amplitude-modulated signal. A digital bandpass filter bandpass-filters a generated amplitude-modulated signal using a predetermined bandpass characteristic, and outputs a resultant signal as a band-extended signal. Further, an adder adds a bandpass-filtered amplitude-modulated signal to the inputted audio signal, and outputs an audio signal including a band-extended signal in an audio signal of an original sound and having an addition result.
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