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DB and voltage relationship

  1. Feb 25, 2010 #1
    does dB increases when voltage increases?can sum1 state or declare a formula or proof?
     
  2. jcsd
  3. Feb 25, 2010 #2
    Decibels are a ratio, nothing more. The convention is that dB's increase as voltage increases. Example:
    Consider a signal with -114 dBm signal power (0 dBm is 1 milliwatt). If the signal voltage increases by a factor of 10, from V1 to V2, what is the signal power?

    20 Log (V2/V1) = 20 Log(10) = 20 dB

    -114 dBm + 20 dB = -94 dBm

    Bob S
     
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