Unable to use a value of type tf as an index. How to fix?

num=[(-number1),(number2)];
            den=[(number3), (number4))];
            sys1 = tf(num, den);
            fb = bandwidth(sys1)
           

Having issues when running this saying that I am unavailable to use value of TF as an index. Any suggestions to fix this?

Answer 1

[Walter Roberson]

You will find that bandwidth is a variable but that you are trying to use it as a function call.

[Rohan Gulur]

Hi Walter, how else would I use bandwidth then?

[Steven Lord]

Rename the variable you've created that's named bandwidth to something else. While that variable exists in the workspace you will be unable to call the bandwidth function.

Answer 2

[Ayush]

Hi @Rohan Gulur

The error message "Unable to use a value of type tf as an index" suggests that there is a syntax error in the code. It seems like there is an extra parenthesis in the den array definition which is causing the problem.

You can try this code:

number1 = ...; % Your value for number1
number2 = ...; % Your value for number2
number3 = ...; % Your value for number3
number4 = ...; % Your value for number4

num = [-number1, number2];
den = [number3, number4];
sys1 = tf(num, den);
fb = bandwidth(sys1);

Thanks,

Ayush

[Rohan Gulur]

It was an issue with my variables in the work space - sorry for the confusion