i am using MATLAB R2007 version in my PC.
i tried to define a transfer function from the following command..
a = tf(,[0.8 1])
but my command window is showing an error like......
" Undefined function or method 'tf' for input arguments of type 'double'."
requesting you to help me on this issue...
The error message is clear: "Undefined function or method 'tf' for input arguments of type 'double'." This mean, that there is no TF function defined for doubles. Even clearing will not change this. The found @dfilt\tf function is obviously defined for dfilt objects.
The call a = tf(,[0.8 1]) is only possible, if you have the Control System Toolbox, see: http://www.mathworks.com/help/control/ref/tf.html
clear tf a = tf(,[0.8 1])
% You, probably used tf as a variable in your script, or you don't have a system control toolbox