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Depending on the signal structure and boundary conditions, discontinuities may occur at the time window limits of the extract taken. These reflect partial oscillations that do not exist at all in reality.

These discontinuities arise if the period of the sampling does not correspond to an integral multiple of the period of the time signal. This occurs with practically every measured signal since this is composed of a number of signals with different period durations.

Window functions are used to suppress these discontinuities. This is done by multiplying the input signal with the window function and supplying the Fourier transform with the resulting signal.

Common window functions are:

•Triangular window

•Hann window

•Hamming window

All of these functions share the fact that they approach zero at the edges, so the periodic continuation now no longer has any jump discontinuities.

 

根据信号结构和边界条件，在提取的时间窗口极限处可能会出现不连续现象。这些反映了现实中根本不存在的部分振荡。

如果采样周期不符合时间信号周期的整数倍，就会出现这些不连续现象。几乎每个测量信号都会发生这种情况，因为这是由一些具有不同周期持续时间的信号组成的。

窗口函数被用来抑制这些不连续现象。这是通过将输入信号与窗函数相乘，并将所得信号进行傅里叶变换来实现的。

常见的窗口函数有：

•三角窗

•汉宁窗

•海明窗

 

All of these functions share the fact that they approach zero at the edges, so the periodic continuation now no longer has any jump discontinuities.

所有这些函数都有一个共同的事实，即它们在边缘接近零，所以现在的周期性延续不再有任何跳跃的不连续。