if dfadeback==2
      dmystepbb
   else
%for i=1:n
%  if db(i)==0
%      db(i);
%   else
%      figure(i+1)
%      dstep(da,db,dc,dd,i);
%   end
%end

 dwindstep=figure('color',[0.8,0.7,0.8],'position',[0.1*winw,0.1*winh,0.8*winw,0.8*winh],...
       'name','離散系統輸出Y(z)和階躍響應','numbertitle','off','menubar','figure',...
       'resize','off');
drr1=size(dfbnum);
drr2=size(dfbden);
dfinderr=0;
%判斷是否為比例環節
if ((drr1(1,2)==1)&(drr2(1,2)==1)),
   dfinderr=1;
   dsysb=tf(dfbnum,dfbden,dhT);
   ddcg=dcgain(dsysb);
   subplot(1,1,1);
   step(dsysb);
   grid on;hold on
   strtext=['這是比例環節，系統指標: 穩態值=' num2str(ddcg) ' ; tr,tp,Mp,ts 無意義 '];
   title(strtext);
else,
n=length(da);
for i=1:n
   de(i,i)=1;
end  
dsysb=dss(da,db,dc,dd,de,dhT);       
ddpb=pole(dsysb);
dii=find(abs(ddpb)>=1);dn1=length(dii);
if (dn1>0)
ddcg=dcgain(dsysb);
[dyc dx]=step(dsysb);
dnsn=length(dyc);dt=1:dnsn;
dyc1=dyc/ddcg;
subplot(2,1,1);
plot(dt,dx,'r');
grid on;hold on
xlabel('s/t');
ylabel('X(z)');
legend('紅線:X(z)狀態曲線',0);
title('X(z)狀態曲線');
subplot(2,1,2);
grid on;hold on
step(dsysb);
 %  plot(t,yc1,'r',t,yc,'b');
grid on;hold on
xlabel('k*T');
ylabel('Y(z)和Y(z)/dcg');
%legend('紅線:Y(z)/dcg階躍響應曲線','藍線:Y(z)階躍響應曲線',0);
strtext=[' 不穩定系統，無穩態值且tr,tp,Mp,ts 無意義 '];
title(strtext); 

else
   
ddcg=dcgain(dsysb);
[dyc dty dx]=step(dsysb);
dnsn=length(dyc);dt=1:dnsn;
dyc1=dyc/ddcg;
subplot(2,1,1);
plot(dt,dx,'r');
grid on;hold on
xlabel('s/t');
ylabel('X(z)');
legend('紅線:X(z)狀態曲線',0);
title('X(z)狀態曲線');
subplot(2,1,2);
grid on;hold on
step(dsysb);
 %  plot(t,yc1,'r',t,yc,'b');
grid on;hold on
xlabel('k*T');
ylabel('Y(z)和Y(z)/dcg');
 
   
  dycn=step(dsysb);
  dtn=length(dycn);
  
  [dycnn dty]=step(dsysb);dcin=length(dycnn);
  %[dz,dp]=ss2zp(dsysb);
  dp=pole(dsysb);  
  uicontrol(dwindstep,'style','push','string','穩態值',...
       'position',[0.06,0.01,0.11,0.05],'units','normalized',...
      'callback','dmysteppre_dcg');
uicontrol(dwindstep,'style','push','string','上升時間tr',...
       'position',[0.22,0.01,0.11,0.05],'units','normalized',...
      'callback','dmysteppre_tr');
uicontrol(dwindstep,'style','push','string','峰值時間tp和最大超調量Mp',...
       'position',[0.37,0.01,0.25,0.05],'units','normalized',...
      'callback','dmysteppre_tpmp');
uicontrol(dwindstep,'style','push','string','調整時間ts',...
       'position',[0.66,0.01,0.11,0.05],'units','normalized',...
      'callback','dmysteppre_ts');
uicontrol(dwindstep,'style','push','string','結束',...
       'position',[0.83,0.01,0.11,0.05],'units','normalized',...
       'callback','dclosestep');
   
end
end
end