1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Transfer Function: Magnitude and Phase of Complex Function

  1. Aug 28, 2012 #1
    1. The problem statement, all variables and given/known data

    f(s) = f([itex]\sigma[/itex] + j[itex]\omega[/itex]) = [itex]\frac{1}{(1+s)^2}[/itex]

    Find the magnitude and phase angle of f(j[itex]\omega[/itex])

    2. Relevant equations

    s = j[itex]\omega[/itex] is a substitution you can make, but I'm not sure if you are supposed to apply that here

    3. The attempt at a solution

    I tried substituting [itex]\sigma[/itex] + j[itex]\omega[/itex] into the function and applying s = j[itex]\omega[/itex].

    Then I get

    [itex]\frac{1}{(\sigma + 1)^2 + 2s(\sigma + 1) + s^2}[/itex]

    I have a feeling it's supposed to be a quadratic pole, but the form of this doesn't match the form of a quadratic pole exactly.
     
  2. jcsd
  3. Aug 29, 2012 #2

    rude man

    User Avatar
    Homework Helper
    Gold Member

    If they ask for f(jw) and they give you f(σ + jw) then σ = 0. So yes, let s = jw and proceed.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook