In
telecommunication, a
preemphasis is a
system process designed to increase, within a
band of frequencies, the magnitude of some (usually higher) frequencies with respect to the magnitude of other (usually lower) frequencies, in order to improve the overall
signal-to-noise ratio by minimizing the adverse effects of such phenomena as
attenuation differences, or
saturation of recording media, in subsequent parts of the system.
Note: Preemphasis has applications, for example, in audio recording and FM transmission.
Source: from Federal Standard 1037C and from MIL-STD-188