m_sequence.m

自己编的基于最抖下降法

function [seq]=create_mseq(connections)
% create_mseq generates the maximal length shift register sequence
% when the shift register connections are given as input to the
% funcion.A "zero" means not connected,ehereas a "one " represents
% a connections
% create_mseq 产生最大的移位寄存器序列。“0”代表没有连接，反之“1”代表连接
m=length(connections)-1;

L=2^m-1; %移位寄存器序列的长度
registers=[zeros(1,m-1) 1]; %寄存器的初始内容
seq(1)=registers(m); %seq表示得到的m序列
for ii=2:L
    s=0;
    new_reg_cont(1)=0;
    for jj=2:m
        new_reg_cont(jj)=registers(jj-1); %移位
    end;
    for jj=1:m
      %  new_reg_cont(1)=mod(new_reg_cont(1)+connections(jj)*registers(jj),2);
      s=connections(jj+1)*registers(jj)+s;
    end
    new_reg_cont(1)=mod(s,2)
    registers=new_reg_cont; % 当前的寄存器内容
    seq(ii)=registers(m); %m序列的下一个元素
end;