substitution in symbolic.

How do i replace 's' with j*w in a transfer function and extract the real and imaginary parts of it in terms of w?

[Walter Roberson]

What is your input? Is it a tf() ? A zpk()? A ss() ? A symbolic expression ?

Answer 1

[Torsten]

syms s w
assume(w,'real')
f = s + s^2;
fs = subs(f,s,1i*w);
fs_real = real(fs)

fs_real = 

fs_imag = imag(fs)

fs_imag = 

w