FFT is applied to the respective zero-padded data; multiplication is applied to the frequency domain; IFFT is applied to the multiplication result, to obtain two discrete-time signals y1[n] and y2[n]; and they are added through an overlap-addmethod, to obtain an output discrete-time signal y[n]. 各ゼロ詰めデータにFFTを行い、周波数領域で乗算し、その乗算結果に対してIFFTを行って、2つの離散時間信号y1[n],y2[n]を得て、重複加算法で加算して、出力離散時間信号y[n]を得る。 - 特許庁