In most RF amplifiers, the gain will vary somewhat over a wide frequency range. Equalizer or Gain Shape pre-amplifiers are used in a number of applications where it's necessary to flatten the gain characteristic of a propagation path. Teledyne Lincoln Microwave has a long heritage of suppling pre-amplifiers into airborne applications where a shaped input gain response to a MPM (Microwave Power Module) or TWT (Traveling Wave Tube) is needed to compensate for the gain variation within the tube.
In order to increase efficiency and to meet the telecommunications
standards the RF amplifier is often used close to compression, where the
device behaves in a non-linear way. Many different techniques have been
proposed and applied to extend the linear range of the power amplifier
response. Linearization techniques such as digital pre-distortion (DPD)
are used to pre-compensate these effects, Although not all RF frontends allow for linearization methods.