Overview

Signal-to-Noise Ratio (SNR) is a measure used to directly compare the strength of a signal relative to background noise. [1] SNR is often expressed in decibles using the equation

where

represents the total signal power and

represents the total noise power. [2]

Shannon-Hartley Theorem

SNR is related to the maximum achievable BER (also referred to as the channel capacity C) and the channel bandwidth B by the Shannon-Hartley Theorem:

where S/N is the SNR not in decibles. [3]

 

Related Links

Modern Optics Article: SNR bounds of FSO links and its evaluation for selected beams