Wayne Parham Messages: 18793 Registered: January 2001
Illuminati (33rd Degree)
It means just what it sounds like it means.
The signal is the information and the noise is everything else. By "information" I mean the content, e.g. audio, video or data. Examples of noise are hiss, hum and digital hash.
So if the signal is 100 times greater than the surrounding noise, then it has a 20dB S/N radio. If it's 1000 times greater, then it has 30dB S/N ratio.