clc;
clear
close all;
M=64;
k=log2(M);
n=120000;
samp=1;
%snr=0:1:14;
x=randint(n,1);
stem(x(1:50),'filled');
title('二进制随机比特流');
xlabel('比特序列');
ylabel('信号幅度');
x6=reshape(x,k,length(x)/k);
xsym=bi2de(x6.','left-msb');
figure;
stem(xsym(1:50));
title('16进制随机信号');
xlabel('信号序列');
ylabel('信号幅度');
y=modulate(modem.qammod(M),xsym);
scatterplot(y);
text(real(y)+0.1,imag(y),dec2bin(xsym));%?
axis([-8 8 -8 8]);
snr=15+10*log10(k)-10*log10(samp);
%snrtem=10.^(snr/10);
%pn=1./snrtem;
%sigma=sqrt(pn);
yn=awgn(y,snr,'measured');
h=scatterplot(yn,samp,0,'b.');
hold on;
scatterplot(y,1,0,'k+',h);% H must be a valid handle to a figure
% that was previously generated by SCATTERPLOT. Default for H is [], which
% causes SCATTERPLOT to create a new figure.
title('接收信号星座图');
legend('含噪声接收信号','不含噪声信号');
axis([-8 8 -8 8]);
hold on;
%eyediagram(yn,2);
yd=demodulate(modem.qamdemod(M),yn);
z=de2bi(yd,'left-msb');
z=reshape(z.',numel(z),1);
[nuber_of_errors,bit_error_rate]=biterr(x,z)
semilogy(snr,bit_error_rate,'ro');
