function re_dcg
global p Cinf 
jj=find(p>=0);
if length(jj)>0
   dcgwdisp=['      穩(wěn)態(tài)值無意義！'];
   helpdlg(dcgwdisp,'時域指標');
else
   %cinf=ycnn(cin);
dcgdisp=['          穩(wěn)態(tài)值 dcg=' num2str(Cinf)];
helpdlg(dcgdisp,'時域指標');
end