How to derive a response plot?

Hi, I have the following response for a transfer function:

sys=tf[...];
impulse(sys);

but the problem is that I want to calculate the numerical derivative of the plot, I can't do the derivative of the tf. So I tried this:

dy=diff(impulse(sys))
plot(dy)

But this gave a graph that it's similar but it's wrong. I tried to take the discrete values of the plot too, but I didn't have good results. Someone know what can I do?

Answer 1

[Ameer Hamza]

See this example

sys = tf(1, [1 2 10]);
[y, t] = impulse(sys);
dy = gradient(y, t);
plot(t, y, 'r', t, dy, 'b')
legend({'y', 'dy/dt'})

[Walter Gazek]

Thank you!

[Ameer Hamza]

I am glad to be of help!