function[y, Outstate]=LinearFeedbackShiftRegister(R,generator,instate,N);
if max(generator)>R
    erro(['the degree of the generator polynomial,',...
        int2str(max(generator)),',can not exceed R,',int2str(R),'.']);
end
if length(instate)>R
    error(['the length of the input state vector,',...
        int2str(length(instate)),',can not exceed R,',int2str(R),'.']);
end
a=sort(generator); P=length(generator);M=length(instate)+1;
for k=1:N
    fee=instate((generator(2)));
    for q=3:P
        fee=bitxor(fee,instate(generator(q)));
    end
    instate=[fee instate];
    y(k)=instate(1);instate(M)=[];
end
Outstate=instate;