Decibels above reference noise

A way to describe noise in terms of reference noise.

dBrn is a notation used to describe noise in terms of reference noise in a circuit. 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, can be indicated in parentheses.

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, 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.

  • dBrn
Adapted from content published on
Last modified on April 27, 2021, 12:39 am is a service provided by Codecide, a company located in Chicago, IL USA.