Numerator and denominator input syntax of matlab control system : (num,den)-CodePudding

I have seen the following form of writing in many matlab routines：

for example, I have a system function

num=1;
den=[1 0 0];
sys=tf(num,den)

If I want to show the step response, or bode plot, I just type

step(sys);
bode(sys);

This I understand.

But I also see another form of writing：

step(num,den);
bode(num,den);

This is an example of stem(num,den)

This is another example of bode2(num,den)

The question is, for the second form, what is the definition of this syntax? I haven't found any detailed explanation of it. I mean, can we use (num,den) to replace sys=tf(num,den)? If so, where can I find some official explanation? Please help! Thanks.

CodePudding user response：

The code you use as an example is written in 1994. This syntax is no longer in use.

Try using the current versions of step and bode.