DBrn
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- The correct title of this article is dBrn. The initial letter is shown capitalized due to technical restrictions.
The symbol dBrn or dB(rn) is an abbreviation for decibels above reference noise.
Weighted noise power in dB is referred to 1.0 picowatt. Thus, 0 dBrn = -90 dBm. Use of 144 line, 144-receiver, or C-message weighting, or flat weighting, must be indicated in parentheses as required.
With C-message weighting, a one-milliwatt, 1000 Hz tone will read +90 dBrn, but the same power as white noise, randomly distributed over a 3 kHz band will read approximately +88.5 dBrn (rounded off to +88 dBrn), because of the frequency weighting.
With 144 weightings, a one milliwatt, 1000 Hz white noise tone will also read +90 dBrn, but the same 3 kHz power will only read +82 dBrn, because of the different frequency weighting.
