数字信号处理课程中利用DFT分析模拟信号频谱的几个问题

Issues on using DFT to analyze analog signal spectrum in the course of digital signal processing

DFT是数字信号处理课程中一种最重要的、应用最广泛的变换。利用DFT可以分析模拟信号的频谱,但谱分析过程中存在频谱混叠、栅栏效应和截断效应等问题。在改善这些问题的同时,需要注意高密度频谱和高分辨率频谱的区别。通过Matlab仿真可以直观明了地观察到这些问题,能有效提高教学效果。

The DFT(Discrete Fourier Transform)is one of the most important and widely used transformations in the course of digital signal processing.DFT can be used to analyze the spectrum of analog signal,but there are some problems in the process of spectrum analysis,such as spectrum aliasing,fence effect and truncation effect.When improving these problems,it is necessary to pay attention to the difference between high-density spectrum and high-resolution spectrum.Matlab simulation can directly and clearly observe these problems,which can effectively improve the teaching effect.