uicontrol('Style','popupmenu',...
             'Units','normalized',...
             'Position',[0.060 0.35 0.15 .1],...
             'foregroundcolor','b',...
             'BackgroundColor',[0.75,0.75,0.75],...
             'String','C1: 1nF|C1: 33nF|C1: 47nF',...
             'value',val_cond,...
             'Callback','val_cond=get(gco,''value''),close,interfata1(R1,R2,val,val_cond,val_cond2,finf,fsup)');


       uicontrol('Style','popupmenu',...
             'Units','normalized',...
             'Position',[0.060 0.375 0.15 .1],...
             'foregroundcolor','b',...
             'BackgroundColor',[0.75,0.75,0.75],...
             'String','C2: 100uF|C2: 68uF|C2: 150uF',...
             'value',val_cond2,...
             'Callback','val_cond2=get(gco,''value''),close,interfata1(R1,R2,val,val_cond,val_cond2,finf,fsup)');


          switch val_cond

              case 1
                  C1=1e-9;
              case 2
                  C1=33e-9;
              case 3
                  C1=47e-9;

          end

            switch val_cond2

              case 1
                  C2=100e-6;
              case 2
                  C2=68e-6;
              case 3
                  C2=150e-6;

            end



f0=1./(2.*pi.*sqrt(R1.*R2.*C1.*C2));
fii=1./(2.*pi.*R1.*C1);
fsi=1./(2.*pi.*R2.*C2);

if fii>fsi
    fsup=fii;
    finf=fsi;
else
    fsup=fsi;
    finf=fii;
end