2fsk误码率matlab程序

%%2fsk误码率的计算%%clearall;closeall;Eb=2;%每比特能量N=100000;%码元数目SNR0=-5;SNR1=20;forj=SNR0:SNR1snr=j;snr1=10^(snr/10);%将信噪比的值由dB转化为数值source=round(rand(1,N));%生成源信号%tb=0.001;%码元周期%ts=tb/10;%抽样周期%t=0:ts:(N*tb-2*ts);fc1=8/tb;%载波1的频率%fc2=4/tb;%载波2的频率%forcsc=1:length(t);source_t(csc)=source(floor(csc/10)+1);%产生数字信号%end%----调制----------carrier1=cos(2*pi*fc1*t);%载波1%carrier2=cos(2*pi*fc2*t);%载波2%fmoded1=source_t.*carrier1;fmoded2=(1-source_t).*carrier2;fmoded=fmoded1+fmoded2;%调制%noise=randn(1,(10*N-1))*(sqrt(Eb/snr1));s_t=fmoded+noise;%加信高斯白噪声%%----相干解调及滤波----------fs_t1=s_t.*carrier1;fs_t2=s_t.*carrier2;fP=(1/tb-500)/5000;%通频%fS=(1/tb+500)/5000;%阻频%[n,w]=buttord(fP,fS,1,20);[b,a]=butter(n,w);%LPF参数%fdemoded1=filter(b,a,fs_t1);%滤波1%fdemoded2=filter(b,a,fs_t2);%滤波2%%----抽样判决----------fdemoded=fdemoded1-fdemoded2;%比较1,2%fori=1:N;y(i)=fdemoded(i*10-2);ify(i)=0;signal(i)=1;elsesignal(i)=0;endend%%%%%%%%%%%%%%%%%计算误码率%%%%%%%%%%%%%a1=find((signal-source)~=0);error1=length(a1);err1(snr-SNR0+1)=error1/N;%仿真误码率err11(snr-SNR0+1)=erfc(sqrt(snr1/2))/2;%理论误码率end%----画图----------x=[SNR0:SNR1];figure(1);semilogy(x,err1,'-*g',x,err11,'-.ob')legend('2FSK仿真误码率','2FPSK理论误码率')xlabel('符号信噪比(dB)');ylabel('误符号率/误比特率');gridon;