COMBINED FEEDBACK AND FEED-FORWARD LINEARISATION OF RF POWER AMPLIFIERS

摘要

A power amplifier module and corresponding system are disclosed for linearising the output from a power amplifier. Both a feedback system, containing a compensator and the power amplifier in a feedback loop, and a pre-distortion compensation system injecting pre-distortion signals into or before the feedback system are used to compensate for non-linearities in the overall system. The pre-distortion signals may be mixed with signals from the compensator or may be filtered to take into account the loop compensator transfer function of the feedback loop, mixed with baseband signals and then converted into analog signals that are provided to the feedback loop. In modules containing a tracking power supply, an envelope calculator calculates an RF envelope of the baseband signals, which the pre-distortion system uses in conjunction with the baseband signals to generate the pre-distortion signals mixed with the signals from the compensator.