golexulei.m

gold序列产生的源程序

%产生L=31的Gold序列，它由取如图9.8所示的两个移位寄存器输出的模2相加而产生。
echo on
%First determine the maximal length shift-register sequences.
%Assume the initial shift-register content as "00001".
connections1=[1 0 1 0 0];
connections2=[1 1 1 0 1];
sequence1=ss_mlsrs(connections1);
sequence2=ss_mlsrs(connections2);
%Cyclically shift the second sequence and add it to the first one.
L=2^length(connections1)-1;
for shift_amount=0:L-1,
    temp=[sequence2(shift_amount+1:L) sequence2(1:shift_amount)];
    gold_seq(shift_amount+1,:)=(sequence1+temp)-floor((sequence1+temp)./2).*2;
    echo off;
end;
echo on;
%Find the max value of the cross-correlation for these sequences.
max_cross_corr=0;
for i=1:L-1,
    for j=i+1:L,
        %equivalent sequences
        c1=2*gold_seq(i,:)-1;
        c2=2*gold_seq(j,:)-1;
        for m=0:L-1,
            shifted_c2=[c2(m+1:L) c2(1:m)];
            corr=abs(sum(c1.*shifted_c2));
            if (corr>max_cross_corr),
                max_cross_corr=corr;
            end;
            echo off;
        end;
    end;
end;
%note that max_cross_correlation turns out to be 9 in this example.