%這是調(diào)制信號的程序
%m是偽碼的相位偏移(1023以內(nèi)),doppler是傳輸中產(chǎn)生的多普勒偏移(在-5000Hz到5000Hz)
function test = modulate(m,doppler)
%產(chǎn)生調(diào)制信號的載波
fc =10.23e+6;
fs = 40.92e+6;
t=0:1/fs:(0.001-1/fs);
T = sin((fc+doppler)*2*pi*t);
%產(chǎn)生擴(kuò)頻碼
n=1023;
[code,cacode]=generate(n);

cacode_A = cacode(1:m);
cacode_B = cacode(m+1:n);
cacode = [cacode_B,cacode_A];
for j =1:1:n
     ca_aftsample((j-1)*40+1:j*40) = repmat(cacode(j),1,40);
end;
%調(diào)制信號并加入白噪聲
test=(-1)*ca_aftsample.* T;
%test = awgn(test, -12, 'measured'); %加高斯白噪聲，信噪比是-12dB