Confusion in Audiogram

Discussion in 'The Projects Forum' started by LoveElecs, Jan 27, 2015.

  1. LoveElecs

    Thread Starter New Member

    Dec 15, 2014
    26
    0
    Hi! I am not familiar with this graph. Can you please explain it to me in a simple manner?
    1. What's with NEGATIVE db?
    2. And i wish to determine the AMPLITUDE. I am confuse if the dB tells the amplitude of the graph.
    Thank you in advance. :rolleyes:
     
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  2. bertus

    Administrator

    Apr 5, 2008
    15,648
    2,347
    Hello,

    The negative numbers on the dB scale indicate that the signals are below the reference level, wich normaly is set as 0 dB.

    Bertus
     
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  3. Reloadron

    Active Member

    Jan 15, 2015
    963
    232
    What bertus said. The term db merely expresses a ratio. For example if we say the reference for 0 dbm (power) is 1 mW (.001 Watt) then it becomes a matter of a 30 db gain would be 1 Watt and a -30 db attenuation would be .000001 Watt. For power it would be calculated as db = 10Log^10* Plarge / Psmall. You can read the Wiki here. In your frequency analysis the spectrum analyzer is telling you that at 608 Hz the signal level is -15 db down from whatever the reference is setup as.Just remember db merely expresses a ratio.

    Ron
     
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  4. LoveElecs

    Thread Starter New Member

    Dec 15, 2014
    26
    0
    i think i have found the answer . Thank you both sir Bertus and sir Ron. :)
     
    Last edited: Jan 27, 2015
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