At any point in a
transmission system
In telecommunications, a transmission system is a communication system that transmits a signal from one place to another. The signal can be an signal (electrical engineering), electrical, fiber-optic communication, optical or radio wave, radio s ...
, the ratio of the
circuit noise
Noise is sound, chiefly unwanted, unintentional, or harmful sound considered unpleasant, loud, or disruptive to mental or hearing faculties. From a physics standpoint, there is no distinction between noise and desired sound, as both are vibrat ...
at that point to an arbitrary level chosen as a reference.
The circuit
noise level is usually expressed in dBrn0, signifying the reading of a circuit noise meter, or in
dBa0, signifying circuit noise meter reading adjusted to represent an interfering effect under specified conditions.
Noise (electronics)
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