imitatecos.m.bak

Galileo BOC 码产生捕获相关仿真结果

clear;
% the center frequency of output cosine wave is 3.76875MHz
N=1024;
n=1:1:N;
y=zeros(1,N);

Accum=0;
for i=1:N,
    Accum=Accum+50;
    if Accum>255
        Accum=Accum-256;
    end
    ac1=fix(Accum/8);
    switch ac1
        case 0,      y(i)=7  + j* 0;  
        case 1,      y(i)=6  + j* 1;  
        case 2,      y(i)=6  + j* 3;  
        case 3,      y(i)=5  + j* 4;  
        case 4,      y(i)=4  + j* 5;  
        case 5,      y(i)=3  + j* 6;  
        case 6,      y(i)=1  + j* 6;  
        case 7,      y(i)=0  + j* 7;  
        case 8,      y(i)=-1  + j* 7; 
        case 9,      y(i)=-3  + j* 7; 
        case 10,     y(i)=-4  + j* 6; 
        case 11,     y(i)=-5  + j* 6; 
        case 12,     y(i)=-6  + j* 5; 
        case 13,     y(i)=-6  + j* 4; 
        case 14,     y(i)=-7  + j* 3; 
        case 15,     y(i)=-7  + j* 1; 
        case 16,     y(i)=-7  + j* 0; 
        case 17,     y(i)=-6  + j* -1;
        case 18,     y(i)=-6  + j* -3;
        case 19,     y(i)=-5  + j* -4;
        case 20,     y(i)=-4  + j* -5;
        case 21,     y(i)=-3  + j* -6;
        case 22,     y(i)=-1  + j* -6;
        case 23,     y(i)=0  + j* -7; 
        case 24,     y(i)=1  + j* -7; 
        case 25,     y(i)=3  + j* -7; 
        case 26,     y(i)=4  + j* -6; 
        case 27,     y(i)=5  + j* -6; 
        case 28,     y(i)=6  + j* -5; 
        case 29,     y(i)=6  + j* -4; 
        case 30,     y(i)=7  + j* -3; 
        case 31,     y(i)=7  + j* -1; 
    end,    
end

yy=zeros(1,32);
for i=1:32,
    yy(i)=y(i);
end
%x=1:32;
%yy2=round(7*cos(2*pi*x/32));
%freq_yy2=fft(yy2);
%plot(abs(freq_yy2))
%yy2 =
%
%  Columns 1 through 10 
%
%     7     6     6     5     4     3     1     0    -1    -3
%
%  Columns 11 through 20 
%
%    -4    -5    -6    -6    -7    -7    -7    -6    -6    -5
%
%  Columns 21 through 30 
%
%    -4    -3    -1     0     1     3     4     5     6     6
%
%  Columns 31 through 32 
%
%     7     7


freq_y=fft(y);
mag_y=abs(freq_y);
%subplot(2,1,1);
%plot(n,y)
%subplot(2,1,2);
plot(n,mag_y)