At any point in a
transmission system
:''See Transmission (mechanics) for a car's transmission system''
In telecommunications, a transmission system is a system that transmits a signal from one place to another. The signal can be an electrical, optical or radio signal.
Some transmiss ...
, the ratio of the
circuit
Circuit may refer to:
Science and technology
Electrical engineering
* Electrical circuit, a complete electrical network with a closed-loop giving a return path for current
** Analog circuit, uses continuous signal levels
** Balanced circu ...
noise
Noise is unwanted sound considered unpleasant, loud or disruptive to hearing. From a physics standpoint, there is no distinction between noise and desired sound, as both are vibrations through a medium, such as air or water. The difference aris ...
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.
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Noise (electronics)