In telecommunications, the term noise power has the following meanings:
The measured total noise in a given bandwidth at the input or output of a device when the signal is not present; the integral of noise spectral density over the bandwidth The power generated by a random electromagnetic process. Interfering and unwanted power in an electrical device or system. In the acceptance testing of radio transmitters, the mean power supplied to the antenna transmission line by a radio transmitter when loaded with noise having a Gaussian amplitude-vs.-frequency distribution. Thermal noise power can be calculated by multiplying the noise spectral density with the signal bandwidth
N p = k B T B , {\displaystyle N_{\text{p}}=k_{\text{B}}TB,}
where:
kB is the Boltzmann constant ≈ 1.38×10−23 J⋅K−1; T is the absolute temperature of the device; and B is the bandwidth.
References This article incorporates public domain material from Federal Standard 1037C. General Services Administration. Archived from the original on 2022-01-22. (in support of MIL-STD-188).