rasymp.m

文件是编辑好的m文件

function sd=rasymp(G)
G=tf(G);num=G.num{1};den=G.den{1};dt=get(G,'inputdelay');p=roots(den);z=roots(num);n=length(p);m=length(z);
if dt==0,if n> m,sd=(sum(p)-sum(z))/(n-m);ds=[];
   if nargout <1, 
    for  i=1:n-m,ds=[ds,sd];end;
    Ga=zpk([],ds,1);hold on;[r,k]=rlocus(Ga);
    for i=1:n-m,plot(real(r(i,:)),imag(r(i,:)),':');end;
   end;
else disp('no asymptote!');sd=[];end;
else a=get(gca,'xlim');b=pi/dt;
    line(a,[b b],'linesty',':');line(a,[-b -b],'linesty',':');end;