QPSK扩频代码

function qpskzlp clear all close all N=20; %随机数点数20 td=0.1; f0=3000; wc=2e4*pi; x=randint(1,N,[0,1]); g=100; %一个矩形电平采样点 %并串转换 z=reshape(x,2,N/2); %并串转换 a=z(1,:); b=z(2,:); figure(1); subplot(311); stem(x,'LineWidth',1.5);grid on; subplot(312); stem(a,'LineWidth',1.5);grid on; subplot(313); stem(b,'LineWidth',1.5);grid on; y1=dpxs(g,a); %I通道脉冲形式 y2=dpxs(g,b); %Q通道脉冲形式 connections =[1 0 0 1]; mseq = m_sequence(connections); %m序列 m=dpxs(100,mseq); %m序列脉冲形式 figure(2); subplot(311); t=linspace(0,td,length(y1)); plot(t,y1,'LineWidth',1.5);grid on; title('I Channel'); axis([0 td -1.5 1.5]); %画I通道电平 subplot(312); t=linspace(0,td,length(y2)); plot(t,y2,'LineWidth',1.5);grid on; title('Q Channel'); axis([0 td -1.5 1.5]); %画Q通道电平 subplot(313); t=linspace(0,(td*2)/N,length(m)); plot(t,m,'LineWidth',1.5);grid on; title('m sequence pulse'); axis([0 td -1.5 1.5]); %画m序列电平 %扩频 out1=kuopinzlp1(N,a); %I通道扩频 out2=kuopinzlp1(N,b); %Q通道扩频 figure(3); subplot(211); t=linspace(0,td,length(out1)); plot(t,out1,'LineWidth',1.5);grid on; title(' I spread spectrum pulse'); axis([0 td -1.5 1.5]); %画I通道扩频图 subplot(212); plot(t,out2,'LineWidth',1.5);grid on; axis([0 td -1.5 1.5]); title('Q spread spectrum pulse'); %画Q通道扩频 %载波调制 y3=(-1)*sin(2*f0*pi*t).*out1; %I通道调制 y4=cos(2*f0*pi*t).*out2; %Q通道调制 y=y3+y4; %QPSK调制 figure(4); subplot(311); t=linspace(0,td,length(out1)); plot(t,y3,'LineWidth',1.5);grid on; title('I Channel Modulation'); axis([0 td -1.5 1.5]); %画I通道调制图 subplot(312); plot(t,y4,'LineWidth',1.5);grid on; title('Q Channel Modulation'); axis([0 td -1.5 1.5]); %画Q通道调制图 subplot(313); plot(t,y,'LineWidth',1.5);grid on; title('QPSK Modulation'); axis([0 td -1.5 1.5]); %画QPSK调制图 %射频调制、解调 t=linspace(0,td,length(y)); f1=y.*cos(wc*t); %射频调制发射 [f,yf]=T2F(t,y); %QPSK调制频域 [f,f1f]=T2F(t,f1); %射频调制频域 r=f1.*cos(wc*t); %射频解调 [f,rf]=T2F(t,r); %射频解调接收频域 [t,l]=lpf(f,rf,3*f0); %经过低通滤波 figure(5); subplot(321); plot(f,abs(yf),'LineWidth',1.5); title('QPSK Modulation fdomain'); grid on; %QPSK调制频域图 subplot(322); plot(t,f1,'LineWidth',1.5); title('fc modulation transmmit'); grid on; %画射频调制发射图 subplot(323); plot(f,abs(f1f),'LineWidth',1.5); title('fc Modulation fdomain'); grid on; %画射频调制发射频域图 subplot(324); plot(t,r,'LineWidth',1.5); title('fc demodulation receive '); grid on; %画射频解调接收图 subplot(325); plot(f,abs(rf),'LineWidth',1.5); title('fc demodulation recieve fdomain'); grid on; %画射频解调接收频域图 subplot(326); plot(t,l,'LineWidth',1.5); title('lowfliter ');grid on; %画经过低通滤波后的图 %载波解调 liremod=(-1)*sin(2*f0*pi*t).*l; %I通道解调 [f,lif]=T2F(t,liremod); [t,iremod]=lpf(f,lif,f0); %经过低通滤波 iremodo=sign(iremod); %波形整形 lqremod=cos(2*f0*pi*t).*l; %Q通道解调 [f,lqf]=T2F(t,lqremod); [t,qremod]=lpf(f,lqf,f0); %%经过低通滤波 qremodo=sign(qremod); %波形整形 t=linspace(0,td,length(l)); figure(6); subplot(321); plot(t,liremod,'LineWidth',1.5); title('I remodulation'); grid on; %画I通路解调图 subplot(323); plot(t,iremod,'LineWidth',1.5); axis([0 td -0.5 0.5]); %画经过低通滤波后的图 t=linspace(0,td,length(liremod)); subplot(325); plot(t,iremodo,'LineWidth',1.5); grid on; title('I remodulation over'); axis([0 td -1.5 1.5]); %波行整形图 subplot(322); plot(t,lqremod,'LineWidth',1.5); title('Q remodulation'); grid on; %画Q通道解调图 subplot(324); plot(t,qremod,'LineWidth',1.5); axis([0 td -0.5 0.5]); %画经过低通滤波后的图 t=linspace(0,td,length(lqremod)); subplot(326); plot(t,qremodo,'LineWidth',1.5); grid on; title('Q remodulation over'); axis([0 td -1.5 1.5]); %波行整形图 %解扩 s=length(m); for i=1:N/2 for j=1:s ij((i-1)*s+j)=iremodo((i-1)*s+j)*m(j); end; end; %将I路解调结果与m相关 for i=1:N/2 ijsum=0; for j=1:s ijsum=ij((i-1)*s+j)+ijsum; end; if(ijsum>=1000); ij1(i)=1; else if(ijsum<=-1000); ij1(i)=-1; end; end; end %根据相关值判决1、-1 ij2=dpxs(g,ij1); t=linspace(0,td,length(ij2)); figure(7); subplot(211); plot(t,ij2,'LineWidth',1.5); grid on; title('I Channel jiekuo'); axis([0 td -1.5 1.5]); %画I通道解扩图 for i=1:N/2 for j=1:s qj((i-1)*s+j)=qremodo((i-1)*s+j)*m(j); end; end; %将Q路解调结果与m相关 for i=1:N/2 qjsum=0; for j=1:s qjsum=qj((i-1)*s+j)+qjsum; end; if(qjsum>=1000); qj1(i)=1; else if(qjsum<=-1000); qj1(i)=-1; end; end; end %根据相关值判决1、-1 qj2=dpxs(g,qj1); t=linspace(0,td,length(qj2)); subplot(212); plot(t,qj2,'LineWidth',1.5); grid on; title('Q Channel jiekuo'); axis([0 td -1.5 1.5]); %画Q通道解扩图 %串并转换 ij1_uni=bi_to_uni(ij1); %I路解扩结果变单极性 qj1_uni=bi_to_uni(qj1); %Q路解扩结果变单极性 ij1_qj1=[ij1_uni;qj1_uni]; x1=reshape(ij1_qj1,1,N); %串并转换 figure(8); subplot(311); stem(x1,'LineWidth',1.5); grid on; subplot(312); stem(ij1_uni,'LineWidth',1.5); grid on; subplot(313); stem(qj1_uni,'LineWidth',1.5); grid on;