Question

matlab求教！以下是代码

% 设定 T=1, 不加噪声
clear all
close all
% 调制
bit_in = randint(1e3, 1, [0 1]);
bit_I = bit_in(1:2:1e3);
bit_Q = bit_in(2:2:1e3);
data_I = -2*bit_I+1;
data_Q = -2*bit_Q+1;
data_I1=repmat(data_I',20,1);
data_Q1=repmat(data_Q',20,1);
for i=1:1e4
data_I2(i)=data_I1(i);
data_Q2(i)=data_Q1(i);
end;
t=0:0.1:1e3-0.1;
f=0:0.1:1;
xrc=0.5+0.5*cos(pi*f);
data_I2_rc=conv(data_I2,xrc)/5.5;
data_Q2_rc=conv(data_Q2,xrc)/5.5;
f1=1;
t1=0:0.1:1e3+0.9;
I_rc=data_I2_rc.*cos(2*pi*f1*t1);
Q_rc=data_Q2_rc.*sin(2*pi*f1*t1);
QPSK_rc=(sqrt(1/2).*I_rc+sqrt(1/2).*Q_rc);
% 解调
I_demo=QPSK_rc.*cos(2*pi*f1*t1);
Q_demo=QPSK_rc.*sin(2*pi*f1*t1);
I_recover=conv(I_demo,xrc);
Q_recover=conv(Q_demo,xrc);
I=I_recover(11:10010);
Q=Q_recover(11:10010);
t2=0:0.05:1e3-0.05;
t3=0:0.1:1e3-0.1;
data_recover=[];
for i=1:20:10000
data_recover=[data_recover I(i:1:i+19) Q(i:1:i+19)];
end;
ddd = -2*bit_in+1;
ddd1=repmat(ddd',10,1);
for i=1:1e4
ddd2(i)=ddd1(i);
end
figure(1)
subplot(4,1,1);plot(t3,I);axis([0 20 -6 6]);
subplot(4,1,2);plot(t3,Q);axis([0 20 -6 6]);
subplot(4,1,3);plot(t2,data_recover);axis([0 20 -6 6]);
subplot(4,1,4);plot(t,ddd2);axis([0 20 -6 6]);
% QPSK误码率分析
SNRindB1=0:2:10;
SNRindB2=0:0.1:10;
for i=1:length(SNRindB1)
[pb,ps]=cm_sm32(SNRindB1(i));
smld_bit_err_prb(i)=pb;
smld_symbol_err_prb(i)=ps;
end;
for i=1:length(SNRindB2)
SNR=exp(SNRindB2(i)*log(10)/10);
theo_err_prb(i)=Qfunct(sqrt(2*SNR));
end;
title('QPSK误码率分析');
semilogy(SNRindB1,smld_bit_err_prb,'*');
axis([0 10 10e-8 1]);
hold on;
% semilogy(SNRindB1,smld_symbol_err_prb,'o');
semilogy(SNRindB2,theo_err_prb);
legend('仿真比特误码率','理论比特误码率');
hold off;
function mainy,
function y=Qfunct(x)
y=(1/2)*erfc(x/sqrt(2));
function[pb,ps]=cm_sm32(SNRindB)
N=10000;
E=1;
SNR=10^(SNRindB/10);
sgma=sqrt(E/SNR)/2;
s00=[1 0];
s01=[0 1];
s11=[-1 0];
s10=[0 -1];
for i=1:N
temp=rand;
if (temp<0.25)
dsource1(i)=0;
dsource2(i)=0;
elseif (temp<0.5)
dsource1(i)=0;
dsource2(i)=1;
elseif (temp<0.75)
dsource1(i)=1;
dsource2(i)=0;
else
dsource1(i)=1;
dsource2(i)=1;
end;
end;
numofsymbolerror=0;
numofbiterror=0;
for i=1:N
n=sgma*randn(size(s00));
if((dsource1(i)==0)&(dsource2(i)==0))
r=s00+n;
elseif((dsource1(i)==0)&(dsource2(i)==1))
r=s01+n;
elseif((dsource1(i)==1)&(dsource2(i)==0))
r=s10+n;
else
r=s11+n;
end;
c00=dot(r,s00);
c01=dot(r,s01);
c10=dot(r,s10);
c11=dot(r,s11);
c_max=max([c00 c01 c10 c11]);
if (c00==c_max)
decis1=0;decis2=0;
elseif(c01==c_max)
decis1=0;decis2=1;
elseif(c10==c_max)
decis1=1;decis2=0;
else
decis1=1;decis2=1;
end;
symbolerror=0;
if(decis1~=dsource1(i))
numofbiterror=numofbiterror+1;
symbolerror=1;
end;
if(decis2~=dsource2(i))
numofbiterror=numofbiterror+1;
symbolerror=1;
end;
if(symbolerror==1)
numofsymbolerror=numofsymbolerror+1;
end;
end;
ps=numofsymbolerror/N;
pb=numofbiterror/(2*N);

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Answer 1

MaLab代码主日期：清除所有&>和[zly]=rownum（数学（2,2,90））#包括