Impedance comm circuits

Discussion in 'General Electronics Chat' started by dexterbateman, Aug 18, 2009.

  1. dexterbateman

    Thread Starter New Member

    Aug 18, 2009
    4
    0
    I wrote this exam and one of the questions was "What is the Impedance of a communication circuit" 150, 300, 600, or 1200 ohm's

    I did not think they where all equal, WTF kind of question is that, the funny part is I was told the result but can't remember

    any ideas

    DeX
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Think telco. One of the figures matches.
     
  3. dexterbateman

    Thread Starter New Member

    Aug 18, 2009
    4
    0
    Thanks for the encripted reply beenthere,

    The number I assume is for input impedance to an antenna or comm cable
     
  4. steveb

    Senior Member

    Jul 3, 2008
    2,433
    469
    The question seems vague to me. Have you left out any information?

    see the following link for more information:

    http://www.epanorama.net/documents/wiring/twistedpair.html

    Here is a quote from there:

     
  5. steveb

    Senior Member

    Jul 3, 2008
    2,433
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    By the way, just to show how vague this question is, it's not even clear that we are talking about the electrical signal domain. If we consider fiber optic optical transmissions, the impedance is close to 300 Ohms for infrared light inside the glass waveguide.
     
  6. dexterbateman

    Thread Starter New Member

    Aug 18, 2009
    4
    0
    I know how open ended the question is, but that is exactly how it was worded. Thanks for all the replies, I did know there where so many techincal people out there. I guess I'am not alone
     
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