1. Limited time only! Sign up for a free 30min personal 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!

Open loop transfer function help

  1. Apr 3, 2016 #1
    1. The problem statement, all variables and given/known data
    upload_2016-4-3_15-17-16.png

    I need to work out the open loop transfer function of the above. I've drawn it on word so it's not great; the + and - represent a summing junction.

    2. Relevant equations
    Everywhere I read, I find a different definition of open loop transfer function. I see G*H is an oft used equation but I'm not sure......



    3. The attempt at a solution
    None!
     
  2. jcsd
  3. Apr 3, 2016 #2

    LvW

    User Avatar

    Your drawing contains a loop of several blocks, correct?
    Do you really have no idea which elements/blocks determine the transfer function of the loop under open conditions?
     
  4. Apr 3, 2016 #3
    No I do not.
     
  5. Apr 3, 2016 #4
    KpKaGcGp / (n + KpkaGcGp) is the answer supposedly but I don't know how this was derived.
     
  6. Apr 3, 2016 #5

    LvW

    User Avatar

    axe34 - no, it is not correct.
    Here is the procedure for measureing/simulating the gain of the open loop.
    You have nothing to do than to open the loop (at any place you like), to inject a test signal and to find the output at the other side of the opening.
    And this procedure gives you the method also for calculating the gain within the complete loop. It is easier as you might think - and it is quite logical!.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted