Through the DFT can transform the complicate Time spectrum to simple frequency spectrum in some special frequencies, which have specific amplitudes relatived to different mass transfer process of ultrasound.

• 通过离散傅里叶变换 ( DFT)将复杂的时域谱转化为频域谱 ；较清楚地将超声对电极反应的影响区分为不同频率下的幅值信号 .