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Effective Noise Power Spectral Density

  1. Jun 30, 2011 #1
    How to calculate the effective noise power spectral density,
    when a noise factor of 3 if given and if said to make any assumptions.

    We know Effective Noise Temperature N = k.Te.B
    I'm assuming it as Te = 290 K x (10 NF/10 - 1) and what about 'B'?
  2. jcsd
  3. Jun 30, 2011 #2


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    A noise factor of 3 means that the effective noise power, referred to the input, is 3 times that of the actual input noise power. I think you've got to make a lot of assumptions to make any conclusions other than that.
  4. Jun 30, 2011 #3
    "B" is bandwidth. The wider your bandwidth the more noise you'll have. For a 1 Hz bandwidth the effective noise power is -174 dBm. For a 1 kHz bandwidth it is -144 dBm, a 30 dB difference both between 1 Hz and 1000 Hz and between -174 and -144 dBm.
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