Cat5e wave form

Discussion in 'General Electronics Chat' started by Nathan Hale, Apr 26, 2017.

  1. Nathan Hale

    Thread Starter Active Member

    Oct 28, 2011
    135
    2
    Hi folks, hope all is well. Can someone tell me if the wave in the pic has a specific name to it? ( like a sine or a cosine or triangular for example).
    I got the wave when I stuck my Oscope probe to one of the connections of my cat5e internet cable.
    Thank you

    p.s. The pic is upside down. sorry about that. inverting it right side up and saving it in paint is not working.

    20170426_183319xxxxxxxxxxx.jpg
     
    Last edited: Apr 26, 2017
  2. MrChips

    Moderator

    Oct 2, 2009
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    Look at the period of the waveform. It is 16ms. That means you're picking up 60Hz line frequency noise. What is connected to the scope probe ground clip?
     
    ronv likes this.
  3. crutschow

    Expert

    Mar 14, 2008
    20,058
    5,649
    Yes.
    It's called 60Hz pickup. ;)
     
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  4. dl324

    AAC Fanatic!

    Mar 30, 2015
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    20170426_183319xxxxxxxxxxx.jpg

    If you were listening to it, it would be called 60 Hz/cycle "hum".
     
  5. Reloadron

    Distinguished Member

    Jan 15, 2015
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    Yeah, 60 Hz noise is what I call it. The picture is also inverted or upside down.

    Ron
     
  6. crutschow

    Expert

    Mar 14, 2008
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    Incidentally the actual ethernet signal is typically a 125MHz digital waveform of 2.5V differential between two of the twisted wire pairs.
     
  7. Nathan Hale

    Thread Starter Active Member

    Oct 28, 2011
    135
    2
    The scope probe ground clip was connected to the probe compensator ground.
     
  8. crutschow

    Expert

    Mar 14, 2008
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    So you were basically looking at the AC mains induced voltage on a floating wire (with respect to your scope ground).
     
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