An increase in signal power between two points, achieved by an active device or system such as an amplifier, which receives an attenuated input signal, applies controlled power to that signal, and outputs a signal that is a function of the input signal, but at a higher power level. Gain is the opposite of attenuation. The gain, or increase, in signal power is typically described in positive decibels (+dB). See also
amplifier,
attenuation, and
dB.