//exec('fstyp12.1.ex')
  hd=[0*ones(1,15) ones(1,10) 0*ones(1,39)];//desired samples
  hst1=fsfirlin(hd,1);//filter with no sample in the transition
  hd(15)=.5;hd(26)=.5;//samples in the transition bands
  hst2=fsfirlin(hd,1);//corresponding filter
  pas=1/prod(size(hst1))*.5;
  fg=0:pas:.5;//normalized frequencies grid
  plot(fg,hst1);
  dess(54:55)=[1;2];
  plot(fg,hst2);
  dess(54:55)=[0;1];
