说明：  PCM/FM信号生成函数，包含基于FM调制以及CPM调制方式，前者是利用matlab中的fm模拟频率调制方式，是对PCM/FM信号比较直观的生成方法，后者是利用CPM信号的生成方法，从相位调制的角度生成。
(Here is PCM/FM signal generating function, including on CPM modulation and FM modulation, the former is the use matlab simulation frequency fm modulation method is PCM/FM signal generation method more intuitive, which is generated using the method of CPM signals, generated from the phase angle modulation.)