Undefined function 'tf' for input arguments of type 'double'.

livefairy

num=[1 1];
>> den=[1 3 6];
>> h=tf(num,den);
Undefined function 'tf' for input arguments of type 'double'.

>> which tf
D:\Program Files\MATLAB\R2012b\toolbox\ident\ident\@idParametric\tf.m  % idParametric method

livefairy

缺少控制工具箱，已解决:)