连续周期信号的傅立叶变换实质上存在两种形式。由于第一种形式的物理意义较为明显,所以该种形式较为常用;第二种形式的优点在于揭示了非周期信号傅立叶变换和由该非周期信号周期延拓后所得周期信号的傅立叶变换的关系,经证明这两种形式实质上是相等的。 There are essentially two forms of Fourier transforms of continuous-period signals. This form is more common due to the obvious physical meaning of the first form. The second form has the advantage of revealing the relationship between the Fourier transform of the non-periodic signal Fourier transform and the periodic signal resulting from the period extension of the aperiodic signal , The two forms proved to be essentially equal.