说明：   本文主要研究内容是3种AM信号数字化解调的算法，即正交解调算法，包络解调算法，平滑离散傅立叶变化（DFT）解调算法，给出相应的解调原理、公式推导以及系统模块。采用MATLAB对一段信号采用3种方法分别进行仿真解调，并对结果进行比较，给出3种方法的优缺点及应用场合。
(This article main research content is three AM signal demodulation algorithm, digital orthogonal demodulation algorithm, namely envelope demodulation algorithm, smooth the discrete Fourier transform (DFT) demodulation algorithm, gives the corresponding demodulation principle, formula deduction and the system module.Using MATLAB simulation using three methods respectively to a signal demodulation, and comparing the results, the advantages and disadvantages of three kinds of methods and applications are presented.)