Definition - What does Noise Signal mean?
Noise signal refers to a ratio that is used in science and engineering to compare the levels of a desired signal with the level of background noise. It is expressed as the ratio of signal power to background noise power and is stated in decibels. A ratio in excess of 1:1 means that there is more signal than noise.
Safeopedia explains Noise Signal
Noise signal is sometimes used informally to refer to any ratio of useful information to irrelevant information. Noise can be defined as unwanted electrical or electromagnetic energy that degrades the quality of signals and data. Noises occurs in digital and analogue systems and can affect files and communications of all types.