Channel noise level

{{Short description |Noise measurement in telecommunications}}

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In telecommunications, the term channel noise level has the following meanings:

1. The ratio of the noise in the communication channel at any point in a transmission system to an arbitrary level chosen as a reference.{{efn|The channel noise level may be expressed in (a) dB above reference noise (dBrn), (b) dB above reference noise with C-message weighting (dBrnC), or (c) adjusted dB (dBa).}}{{efn|Each unit used to measure channel noise level reflects a circuit noise reading of a specialized instrument designed to account for different interference effects that occur under specified conditions.}}
2. The noise power spectral density in the frequency range of interest.
3. The average noise power in the frequency range of interest.