关于离散傅里叶变换频率分辨率的讨论

频率分辨率是数字信号处理课程教学中一个重要的概念，因为它决定了DFT参数的选择。在现有的数字信号处理的书籍中，一般认为DFT频率分辨率为△f=fs/Nn文中首先通过一个实例指出了这种定义的局限性，然后以两个等幅单频信号为例，对Ⅸ叮测频分辨率进行了详细分析。文中分析了Ⅸ叮频率分辨率定义局限性产生的原因．以及信号相位对DFT测频分辨率的影响，并给出了相应Matlab仿真结果。最后，对DFT频率分辨率定义进行了扩展和修正。

Discussion about the Frequency Resolution of the Discrete Fourier Transform

The frequency resolution is an important concept in the digital signal processing teaching, because it effects the DFT parameter choice. The frequency resolution of DFT is fs/N, which is generally thought in the eiisted textbooks of digital sigual proccssing. In this article, it points out the limitation of this kind of definition through an example first. Then, it analyzes the frequency resolution by taking a two-constantamplitude monofrequent signal as an example. In this paper it analyzes the reason why the definition of frequency resolution is limited and the influence by the signal phase. In the following, it gives the corre- sponding Matlab simulation result, Some extension and modification of the frequency resolution are presented at last.