Signal-to-noise ratio Formula

Signal-to-noise ratio (SNR or S/N) is a measure used in science and engg that compares the level of a desired signal to the level of background noise.

SNR is as the reciprocal of the coefficient of variation i.e the ratio of mean to standard deviation of a signal or measurement

= μ / σ

where

μ is the signal mean or expected value

σ is the standard deviation of the noise or an estimate thereof