createsource.m

gps/galileo信号源频谱分析

function [Signal_Source, Noise_Source]=CreateSource(phcode,fd,ph,AWGNflag)
% data speed 250bit/s
% choose one 4ms
global time_unit;
global time;
global fs;
global nn
global kk;
global F_if ;
global CA_Freq;
global CA_length;
global NOISE_POWER;

Tr_data = [];
data = [];
SNR = -15;
MBuffer=[];
data_change = time/time_unit;

for n = 1:data_change
    Tr_data = [Tr_data (ceil(rand-0.5)*(-2)+1)*ones(1,time_unit/CA_length)];  %ceil向上取整
end
data = Tr_data;   %添加训练序列的待发送数据
for i = 1:1:length(data)
    Md_f = data(i);
    Md_m = Modulate(Md_f,phcode,fd,i);
    MBuffer = [MBuffer Md_m];
end 
MBuffer;


t = [0:kk-1];
Carr = cos(((2*pi*(F_if-fd).*t)./fs)+ph);
S_Code=MBuffer.*Carr;

if AWGNflag == 1
   [Signal_Noise,Noise] = AWGN(S_Code,SNR);
   RxSignal = Signal_Noise;   %噪声标志为1时加入高斯白噪声
   RxNoise = Noise;
else
   RxSignal =S_Code;   %噪声标志为0时,不加入噪声
   RxNoise = 0;
end    
 Signal_Source=RxSignal;
 Noise_Source = RxNoise;