离散时间傅里叶变换有时也称为序列傅里叶变换。离散时间傅里叶变换实质上就是单位圆上的(双边)Z变换。当时域信号为连续信号时，用连续时间傅里叶变换；为离散信号时，用离散时间傅里叶变换。-Discrete-time Fourier transform is sometimes referred to as sequence Fourier transform. Discrete-time Fourier transform is essentially the unit circle (bilateral) Z transform. Time domain signal is continuous signal, with continuous time Fourier transform　as discrete signals, discrete-time Fourier transform.