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Noise Margin and SNR

Discussion in 'Internet, Connectivity and Communications' started by arisen, Feb 19, 2006.

  1. arisen

    arisen Byte Poster

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    Can someone help me out with this, i'm wondering if Noise Margin and Signal to Noise Ratio (SNR) are one and the same thing??

    [​IMG]

    If i'm getting a Noise Margin downstream of 14dB, that aint good is it? However, my line attenuation is 15dB down, 4.5dB up. (I live within 100m of my exchange, teh-hee)

    So low attenuation, which is good, but low noise margin, which is bad?

    Anyone shed some light on this for me? 8) Cheeeers
     
    Certifications: BEng, PRINCE2, ITIL, Net+
    WIP: MSc, Linux+ 2009, RHCE
  2. simongrahamuk
    Honorary Member

    simongrahamuk Hmmmmmmm?

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    *BUMP* :biggrin
     
  3. MarkN

    MarkN Nibble Poster

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    Signal to noise and noise margin are one and the same, here in the UK we tend to use the term "signal to noise".

    noise refers to any interference on the physical medium that makes it difficult for the rx to detect the data signal. Some level of noise on the medium is inevitable but that acceptable level of noise must be kept to a minimum.

    Attenuation is the decrease in signal amplitude over the length of a link, long cable links and high signal frequencies contribute to greater signal attenutaion, attentuation is expressed in decibels (dB) using negative numbers, smaller negative dB values are indication of better link performance.
     
    Certifications: MCSE NT4\W2K,CNE,CCEA,ASE
    WIP: CCNA
  4. Boycie
    Honorary Member

    Boycie Senior Beer Tester

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    Your lucky, my line loss is worse than yours. :(
     
    Certifications: MCSA 2003, MCDST, A+, N+, CTT+, MCT
  5. arisen

    arisen Byte Poster

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    Thanks MarkN!

    My SNR is quite low (bad) because i have some dodgy extensions running to my room where my PC is located, i'm hopefully going to just plug my router into my master socket and run wirelessly from now on which should increase my SNR.
     
    Certifications: BEng, PRINCE2, ITIL, Net+
    WIP: MSc, Linux+ 2009, RHCE

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