gusucode.com > matlab通信工程仿真源码（张德丰等编著）程序书籍 > matlab_code/matlab通信工程仿真源码（张德丰等编著）/第8章/li8_6.m

    Fs=10000; %仿真的采样率
t=1/Fs:1/Fs:1; %仿真时间点
m_t(Fs*1)=0; %基带信号变量初始化
for f=150:400  %基带信号发生：频率150~400Hz
    m_t=m_t+0.01*sin(2*pi*f*t)*(400-f);%幅度随线性递减
end
m_t90shift=imag(hilbert(m_t)); %基带信号的希伯尔特变换
carriercos=cos(2*pi*1000*t); %1000载波cos
carriersin=sin(2*pi*1000*t); %1000Hz正交载波sin
S_SSB1=m_t.*carriercos-m_t90shift.*carriersin;  %上边带SSB
S_SSB2=m_t.*carriercos+m_t90shift.*carriersin;  %下边带SSB
%下面作出各波形以及频谱
figure;
subplot(421);
plot(t(1:100),carriercos(1:100),t(1:100),carriersin(1:100),':m');%载波
subplot(422);
plot([0:9999],abs(fft(carriersin)));%载波频谱
axis([0 2000 -500 12000]);
subplot(423);
plot(t(1:100),m_t(1:100)); %基带信号
subplot(424);
plot([0:9999],abs(fft(m_t)));%基带频谱
axis([0 2000 -500 12000]);
subplot(425);
plot(t(1:100),S_SSB1(1:100)); %SSB波形上边带
subplot(426);
plot([0:9999],abs(fft(S_SSB1))); %SSB波形上边带
axis([0 2000 -500 12000]);
subplot(427);
plot(t(1:100),S_SSB2(1:100)); %SSB波形下边带
subplot(428);
plot([0:9999],abs(fft(S_SSB2))); %SSB波形下边带
axis([0 2000 -500 12000]);