According to Wikipedia, “signal-to-noise” 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 noise power." We have operated in and will continue to operate in an environment where the signal has been extremely low.

In classical physics, there is a seemingly magical machine, called a lock-in amplifier, that extracts signal from the deepest and darkest pits of noise.