%输入信号
>> subplot(4,1,1);
>> t=0:0.001:8;
>> d=[0 0 ;0.5 1;1 1;1.5 0;2 1 ;2.5 1;3 0;3.5 0;4 0;4.5 1 ;5 1 ;5.5 0 ;6 1 ;6.5 1 ;7 0 ;7.5 0];
>> s=pulstran(t-0.25,d,'rectpuls',0.5);plot(t,s) ;
>> axis([0 8 -0.5 1.5]);
>> text(0.25,1.2,'0') ; text(0.75,1.2,'1') ; text(1.25,1.2,'1') ; text(1.75,1.2,'0') ;
>> text(2.25,1.2,'1') ; text(2.75,1.2,'1') ; text(3.25,1.2,'0') ; text(3.75,1.2,'0') ;
>> text(4.25,1.2,'0') ; text(4.75,1.2,'1') ; text(5.25,1.2,'1') ; text(5.75,1.2,'0') ;
>> text(6.25,1.2,'1') ; text(6.75,1.2,'1') ; text(7.25,1.2,'0') ; text(7.75,1.2,'0') ;

% I路信号
>> subplot(4,1,2);
>> t=0:0.001:8;
>> a=1/sqrt(2);
>> d=[0 -a ;1 +a;2 -a;3 +a; 4 -a ;5 +a;6 -a;7 +a];
>> s=pulstran(t-0.5,d,'rectpuls');plot(t,s) ;
>> axis([0 8 -2 2]);
>> text(0.5,1.5,'-0.7') ; text(1.5,1.5,'+0.7') ;text(2.5,1.5,'-0.7') ;text(3.5,1.5,'+0.7');
>> text(4.5,1.5,'-0.7') ; text(5.5,1.5,'+0.7') ;text(6.5,1.5,'-0.7') ;text(7.5,1.5,'+0.7');

% Q路信号
>> subplot(4,1,3);
>> t=0:0.001:8;
>> d=[0 +a;1 -a;2 -a;3 +a; 4 +a;5 -a;6 -a;7 +a];
>> s=pulstran(t-0.5,d,'rectpuls');plot(t,s) ;
>> axis([0 8 -2 2]);
>> text(0.5,1.5,'+0.7') ; text(1.5,1.5,'-0.7') ; text(2.5,1.5,'-0.7') ; text(3.5,1.5,'+0.7')
>> text(4.5,1.5,'+0.7') ; text(5.5,1.5,'-0.7') ; text(6.5,1.5,'-0.7') ; text(7.5,1.5,'+0.7')

%QPSK调制信号
>> subplot(4,1,4);
>> t=0:0.001:8;
>> d1=[0 -a ;1 +a;2 -a;3 +a; 4 -a ;5 +a;6 -a;7 +a];
>> s1=pulstran(t-0.5,d1,'rectpuls').*cos(2*pi*5*t) ;
>> d2=[0 +a;1 -a;2 -a;3 +a; 4 +a;5 -a;6 -a;7 +a];
>> s2=pulstran(t-0.5,d2,'rectpuls').*sin(2*pi*5*t);
>> plot(t,s1-s2) ;
>> axis([0 8 -2 2]);
>> text(0.3,1.5,'3\pi/4') ; text(1.3,1.5, '7\pi/4') ; text(2.3,1.5,'5\pi/4') ; text(3.3,1.5,'\pi/4') ;
>> text(4.3,1.5, '3\pi/4') ; text(5.3,1.5, '7\pi/4') ; text(6.3,1.5,'5\pi/4') ; text(7.3,1.5,'\pi/4') ;