Signal-to-noise ratio (abbreviated
SNR or
S/N) is a measure used in science and engineering that compares the level of a desired
signal to the level of background
noise. It is defined as the ratio of signal power to the noise power, often expressed in
decibels. A ratio higher than 1:1 (greater than 0 dB) indicates more signal than noise. While SNR is commonly quoted for electrical signals, it can be applied to any form of signal (such as isotope levels in an
ice core or
biochemical signaling between cells).