搜索
%%%%%%%通信原理OOK信号仿真、功率谱和相干解调分析演示clccloseallclearallcodn=60;%仿真的码元个数fc=6e+3;%载波频率fs=fc*6;%数据采样率bode=1000;%信号波特率code=round(rand(1,codn));%产生随机信码（round：最近整数四舍五入）code_len=round(1/bode/(1/fs));%得到一个码元周期的数据长度fori=1:codn%产生数字基带信号x((i-1)*code_len+1:code_len*i)=code(i);endcar=cos(2*pi*fc/fs*(0:length(x)-1));%产生载波y=x.*car;%ook信号等于单极性数字基带信号乘以载波figuresubplot(211)plot(x)axis([0length(x)-0.51.5])gridonzoomontitle('原始基带信号')subplot(212)plot(y)zoomongridontitle('OOK信号')ay=abs(fft(y));%进行幅频特性分析f=0:fs/length(y):fs/2;ay=ay(1:length(f));figureplot(f,ay)zoomongridontitle('OOK的频谱')z=y.*car;%相干解调fl=fir1(64,fc/fs*2);%低通滤波z=2*filter(fl,1,z);figuresubplot(211)plot(x)axis([0length(x)-0.51.5])gridontitle('原始基带信号')subplot(212)plot(z)axis([0length(x)-0.51.5])gridontitle('解调得到的基带信号')zoomon