I am trying to use the tf function to enter a filter response, but upon entering this in matlab 6.0 Release 12 num=[kd, kp, ki]; den=[1 0]; sys=tf(num,den); it says: " ??? Undefined function or variable 'tf'. " Anybody knows the library I'd have to download to be able to get this up and running? I'd appreciate your help enormously, David. |