hdb3.m

用matlab打开即可

function x_HDB3=HDB3(x,Previous_s,Previous_v)
N=length(x);
x_HDB3=zeros(1,N);
%initial the register:
%Previous_s:前一非零符号的极性；Previous_v:前一破坏点的极性；
%Previous_s=-1;Previous_v=-1;
i=1;
while(i<=N-3)
    if(x(i)==1)
        x_HDB3(i)=-1*Previous_s;
        Previous_s=x_HDB3(i);
        i=i+1;
    elseif(x(i)==0)
        if(x(i+1)==1)
            x_HDB3(i)=0;x_HDB3(i+1)=-1*Previous_s;
            Previous_s=x_HDB3(i+1);
            i=i+2;
        elseif(x(i+1)==0)
            if(x(i+2)==1)
                x_HDB3(i)=0;x_HDB3(i+1)=0;x_HDB3(i+2)=-1*Previous_s;
                Previous_s=x_HDB3(i+2);
                i=i+3;
            elseif(x(i+2)==0)
                if(x(i+3)==1)
                   x_HDB3(i)=0;x_HDB3(i+1)=0;x_HDB3(i+2)=0;x_HDB3(i+3)=-1*Previous_s;
                   Previous_s=x_HDB3(i+3);
                   i=i+4; 
                elseif(x(i+3)==0)
                %here deal with the four zeros groups
                    if(Previous_s==1 & Previous_v==1)
                        x_HDB3(i)=-1;x_HDB3(i+1)=0;x_HDB3(i+2)=0;x_HDB3(i+3)=-1;Previous_s=x_HDB3(i+3);Previous_v=x_HDB3(i+3);i=i+4;
                    elseif(Previous_s==-1 & Previous_v==-1)
                        x_HDB3(i)=1;x_HDB3(i+1)=0;x_HDB3(i+2)=0;x_HDB3(i+3)=1;Previous_s=x_HDB3(i+3);Previous_v=x_HDB3(i+3);i=i+4;                            
                    elseif(Previous_s==-1 & Previous_v==1)
                        x_HDB3(i)=0;x_HDB3(i+1)=0;x_HDB3(i+2)=0;x_HDB3(i+3)=-1;Previous_s=x_HDB3(i+3);Previous_v=x_HDB3(i+3);i=i+4;                            
                    elseif(Previous_s==1 & Previous_v==-1)                            
                        x_HDB3(i)=0;x_HDB3(i+1)=0;x_HDB3(i+2)=0;x_HDB3(i+3)=1;Previous_s=x_HDB3(i+3);Previous_v=x_HDB3(i+3);i=i+4;                            
                    end    
                end
            end
        end
    end
end
for j=i:1:N
    if(x(j)==1)
        x_HDB3(j)=-1*Previous_s;Previous_s=x_HDB3(j);        
    elseif(x(j)==0)
        x_HDB3(j)=0;
    end    
end
return;