bpsk.m

交全面的给出了好几种调制解调方案的matlab代码,又ASK,BPSK,FSK,QAM等的源代码 对通信领域的研究人员很有帮助

function [y,Kmod,fs,fb,fc,rd]=bpsk(x,Kmod,Kbase,fs,fb,fc,rd);
%
% Usage:[y,Kmod,fs,fb,fc,rd]=bpsk(x,Kmod,Kbase,fs,fb,fc,rd);x为二进制码流的向量:参数
%Kmod=1表示BPSK调制,=2,表示DPSK调制,Kbase=1表示不采用基带波形,=2表示采用基带波形,rd为微分编码的初始参考相位,y为已调
%信号
if nargin<7; rd=0; end;
if nargin<6; fc=2; end;
if nargin<5; fb=1; end;
if nargin<4; fs=32;end;
if nargin<3; Kbase=1;end;
if nargin<2;Kmod=1; end; % Kmod=1,2PSK;Kmod=2,2DPSK;
if nargin<1;x=[0 0 1 1 1 0 0 1 0 1 1 0 0 0 1 0];end;
T=length(x)/fb;m=fs/fb;dt=1/fs;t=0:dt:T-dt;
Kmod=rem(Kmod,2);Kmod=Kmod+(Kmod==0)*2;rd=rem(rd,2);
Kbase=rem(Kbase,2);Kbase=Kbase+(Kbase==0)*2;
if Kmod==1;
    x1=1-x*2;tstr='BPSK';
elseif Kmod==2;
    x1=dcode(x,rd);% rd-rference digit
    x1=1-rem(x1,2)*2;
    tstr=['DPSK(reference digit:int2str(rd))'];
end;
if Kbase==1;
    y=pulse(x1,m).*sin(2*pi*fc*t);
elseif Kbase==2;
    x2=pulse(x1,m);x2=bshape(x2);%fs,fb,N,alfa);
    y=x2.*sin(2*pi*fc*t);
end;
I=find(abs(y)<1e-09&[diff(y) 0]>0);
mm=fs/fc;I=rem(I,mm);I=I+(I==0)*mm;
ph=(m-I+1)*2*pi/mm;ph=rem(ph,2*pi);
%--------------------------------------------------------
if nargout<1;
    subplot(211);
    if Kbase==1;
        plot([t T],[y y(1)],t,pulse(x,m)-.5,[0 T],[0 0],'b:');axis([20,40,-1,1]);
    elseif Kbase==2;
        plot([t T],[y y(1)],t,-x2*.5,[0 T],[0 0],'b:');axis([20,40,-1,1]);
        tstr=[tstr 'with the RC filter'];
    end; title('Signal');
    n=length(y);y=fft(y)/n;y=abs(y(1:fix(n/2)))*2;
    I=find(y<1e-04);y(I)=1e-04;y=20*log10(y);
    f1=m/n;f=0:f1:(length(y)-1)*f1;
    subplot(223); plot(f,y,'r');axis([0,10,-80,0]); grid on;
    title('Spectrum');xlabel('f/fb');zoom xon;
    subplot(224);H=polar(ph,ones(size(ph)),'ro');
    set(H,'markers',8,'linew',2);xlabel('Phase');
    set(gcf,'num','off','name',['tstr','blanks(10)','BBI 2000']);
end;