Channel noise level

1. The ratio of the channel noise at any point in a transmission system to an arbitrary level chosen as a reference.

Note 1: 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).

Note 2: 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 density[?] spectrum in the frequency range[?] of interest.

3. The average noise power in the frequency range of interest.

Source: from Federal Standard 1037C and from MIL-STD-188