hu2_msk_270k.m

msk调制——参照原理框图——新手望各位高手指教

clf;clc;clear;close all;
t=0:1/(16*270833):5023/(16*270833);
Rb=270833;T=1/Rb;fc=900000000;
% Gauss_coeff=[-0.00761372008807 0.507613720088070 0.507613720088070 -0.007613720088070];
%Gauss_c=[-0.0076 0.5076 0.5076 -0.0076];
source=round(rand(1,314));
for i=1:length(source)
    if source(i)==0
        source(i)=-1;
    end;
end;
%  source1=source;
%  source=filter(Gauss_coeff,1,source1);

si=source(1,1:2:314);
sq=source(1,2:2:314);
sii=ones(1,157*32);
sqq=ones(1,157*32);
for i=1:length(si)
    for k=1:32
        sii((i-1)*32+k)=si(i);
        sqq((i-1)*32+k)=sq(i);
    end;
end; 
sqq=[zeros(1,16) sqq(1,1:length(sqq)-16)];
mbi=sii.*cos(pi*t/(2*T)-pi/2);
mbq=sqq.*sin(pi*t/(2*T)+pi/2);
%--------
t1=0:1/fc/16:5023/fc/16;
mi=mbi.*cos(2*pi*fc.*t1);
mq=mbq.*sin(2*pi*fc.*t1);
msk=mi+mq;
%------
plot(t,mbi,'b');
hold on;
plot(t,mbq,'r');
bb=cos(pi*t/(2*T)-pi/2);
plot(t,bb,'go');
axis([0 0.00012 -1 1])
hold off;
%----
figure;
hold on;
plot(t1,mi);
plot(t1,mq,'g')
axis([0 0.00000002 -1 1])
hold off;
figure;
plot(t1,msk,'y');
axis([0 0.00000002 -1 1])
%------
figure;
plot(mbi,mbq);
%-------
msk_f=fft(msk,262144);
msk_p=msk_f.*conj(msk_f)/262144;
figure;
plot(msk_p);
msk_p1=10*log10(msk_p);
figure;
plot(msk_p1);
axis([0,130000,-90,0])
eyediagram(msk,128);
%--------
t2=0:1/270833:313/270833;
cc(1)=0;
for i=2:length(t2)
    cc(i)=source(i-1)*pi*(t2(i)-t2(i-1))/(2*T)+cc(i-1);
end;    
figure;
plot(t2,cc);
axis([0 0.0002 -10 10])
%---------