相位调制matlab

%PM调制figure('Name','信号调制过程中波形及其频谱','NumberTitle','off')a0=2;f0=10;fc=50;fs=1000;snr=5;t=linspace(-20,20,60001);pm1=cos(2*pi*f0*t);%信息信号t1=cos(2*pi*fc*t);%载波s_pm=cos(2*pi*fc*t+1*pm1);PM1=fft(pm1);T1=fft(t1);S_PM=fft(s_pm);f=(0:60000)*fs/60001-fs/2;subplot(3,2,1);plot(t(19801:202