clear?all
close?all
i=10;
j=5000;
t=linspace（05j）;
fc=10;
fm=i/5;
B=2*fc;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%產(chǎn)生基帶信號(hào)
a=round（rand（1i））;%隨機(jī)序列
figure（2）
plot（rand（1i））
st=t;
for?n=1:10
????if?a（n）<1;
????????for?m=j/i*（n-1）+1:j/i*n
????????????st（m）=0;
????????end
????else
????????for?m=j/i*（n-1）+1:j/i*n
????????????st（m）=1;
????????end
????end
end
figure（1）;
subplot（421）;
plot（tst）;
axis（[05-12]）;
title（‘基帶信號(hào)‘）;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%載波
s1=cos（2*pi*fc*t）;
subplot（422）;
plot（s1）;
title（‘載波信號(hào)‘）;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%調(diào)制
e_2ask=st.*s1;
subplot（423）;
plot（te_2ask）;
title（‘已調(diào)信號(hào)‘）;
noise?=rand（1j）;
e_2ask=e_2ask+noise;%加入噪聲
subplot（424）;
plot（te_2ask）;
title（‘加入噪聲的信號(hào)‘）;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%相干解調(diào)
at=e_2ask.*cos（2*pi*fc*t）;
at=at-mean（at）;
subplot（425）;
plot（tat）;
title（‘相乘后信號(hào)‘）;
[faf]?=?T2F（tat）;%通過低通濾波器
[tat]?=?lpf（faf2*fm）;
subplot（426）;
plot（tat）;
title（‘解調(diào)后波形‘）;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%抽樣判決
for?m=0:i-1;
if?at（1m*500+250）+0.5<0.5;
????for?j=m*500+1:（m+1）*500;
????????at（1j）=0;
????end
else
????for?j=m*500+1:（m+1）*500;
????????at（1j）=1;
????end
end
end
subplot（427）;
plot（tat）;
axis（[05-12]）;
title（‘抽樣判決后波形‘）
????????

?屬性????????????大小?????日期????時(shí)間???名稱
-----------?---------??----------?-----??----

?????文件???????2553??2008-07-10?16:00??DPSK.m

?????文件????????451??2008-09-05?08:17??jd.m

?????文件????????483??2008-07-04?15:07??T2F.m

?????文件????????351??2008-07-04?15:07??F2T.m

?????文件????????469??2008-09-04?21:42??lpf.m

?????文件???????1371??2008-07-10?21:29??ASK.m

?????文件???????1907??2008-07-10?15:11??FSK.m

?????文件???????1618??2008-07-10?15:54??PSK.m

-----------?---------??----------?-----??----

?????????????????9203????????????????????8