Control

INSTITUTO POLITECNICO NACIONAL

ESCUELA SUPERIOR DE INGENERIA MECANICA
ELECTRICA

ESIME ZACATENCO

COMUNICACIONES DIGITALES

ALUMNO
Martínez Sarabia David Eduardo

PROFESOR
ArturoPérez Martínez
GRUPO
6CM5

function qpskd(g,f)
%For more information, visit: www.matpic.com
%Modulation QPSK
%Example: g is a binay vector; f is the carrier frequency.
%qpskd([1 0 1 1 00],2)
%Author. Diego Orlando Barragán Guerrero
%diegokillemall@yahoo.com
%Loja (ECUADOR)
%See also:%http://www.mathworks.com/matlabcentral/fileexchange/loadFile.do?objectId=14328&objectType=FILE
if nargin > 2
error('Too many input arguments');
elseif nargin==1
f=1;
end

if f<1;
error('Frequency must be bigger than 1');
end
%*-*-*-*-*-*
l=length(g);r=l/2;
re=ceil(r);
val=re-r;

if val~=0;
error('Please insert a vector divisible for 2');
end
%*-*-*-*-*-*
t=0:2*pi/99:2*pi;
cp=[];sp=[];
mod=[];mod1=[];bit=[];
for n=1:2:length(g);if g(n)==0 && g(n+1)==1;
die=sqrt(2)/2*ones(1,100);
die1=-sqrt(2)/2*ones(1,100);
se=[zeros(1,50) ones(1,50)];
elseif g(n)==0 && g(n+1)==0;die=-sqrt(2)/2*ones(1,100);
die1=-sqrt(2)/2*ones(1,100);
se=[zeros(1,50) zeros(1,50)];
elseif g(n)==1 && g(n+1)==0;
die=-sqrt(2)/2*ones(1,100);die1=sqrt(2)/2*ones(1,100);
se=[ones(1,50) zeros(1,50)];
elseif g(n)==1 && g(n+1)==1;
die=sqrt(2)/2*ones(1,100);
die1=sqrt(2)/2*ones(1,100);se=[ones(1,50) ones(1,50)];
end
c=cos(f*t);
s=sin(f*t);
cp=[cp die]; %Amplitude cosino
sp=[sp die1]; %Amplitude sino
mod=[mod c]; %cosino carrier (Q)mod1=[mod1 s]; %sino carrier (I)
bit=[bit se];
end
bpsk=cp.*mod+sp.*mod1;
subplot(2,1,1);plot(bit,'LineWidth',1.5);grid on;
title('Binary Signal')
axis([0 50*length(g) -1.5 1.5]);...