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| clear all;
fe=10000;
T=3;
f0=150;
fech=100;
deltaf=8;
nbcanaux=5;
t=(0:1/fe:T-1/fe);
nech=fech*T;
R=4;
rolloff=0.5;
nsym=T*R;
delay=2;
Tretard=delay/R;
Tobs=T+2*Tretard;
ne=fe*T;
nretard=Tretard*fe;
nf=ne+2*nretard;
nec=fe/R;
tf=(0:1/fe:Tobs-1/fe)';
for i=1:nbcanaux
bp(:,i)=2*ceil(rand(1,nsym)-0.5)-1;
bq(:,i)=2*ceil(rand(1,nsym)-0.5)-1;
% for i=1:nsym
% for j=1:nec
% bps((i-1)*nec+j)=bp(i);
% bqs((i-1)*nec+j)=bq(i);
% end
% end
fc(i)=f0+deltaf*(i-ceil(nbcanaux/2));
bpsf(:,i)=rcosflt(bp(:,i),R,fe,'fir/normal',rolloff,delay);
bqsf(:,i)=rcosflt(bq(:,i),R,fe,'fir/normal',rolloff,delay);
qpsk(:,i)=real(j*bqsf(:,i)+bpsf(:,i).*exp(-j*2*pi*fc(i)*tf));
% figure(i);
% plot(tf,qpsk(:,i));grid;
% figure(10+i);
% plot((0:1/nf:1-1/nf)*fe,20*log(abs(fft(qpsk(:,i)))));
% grid;
end
x=sum(qpsk,2);
figure(1);
plot(tf,x);grid;
figure(2);
plot((0:1/nf:1-1/nf)*fe,20*log(abs(fft(x))));
grid; |
