【摘要】 信号处理中离散傅里叶变换DFT是一个重要的计算手段，可以完成很多计算，包括对连续时间信号的频谱估计。这在教学中是一个重点和难点。构建了由连续时间傅里叶变换CTFT和离散时间傅里叶变换DTFT导出DFT的过程，通过一系列操作和推导，以此理解DFT和DTFT以及离散时间傅里叶级数DTFS的密切联系，并深刻体会利用DFT做频谱分析的特点和考虑。更多还原

【Abstract】 Discrete Fourier transform(DFT) is an important calculation method in signal processing, which can do many calculations, including spectrum estimation of continuous time signals. It is a key and difficult point in teaching. This paper constructs a process of deriving DFT from continuous time Fourier transform(CTFT) and discrete time Fourier transform(DTFT). Through a series of operations and derivation, the process is helpful to understand the close relationship between DFT, DTFT and discrete time Fourier series(DTFS), and deeply understand the characteristics and considerations of spectrum analysis using DFT.更多还原