Doherty amplifier system

A Doherty amplifier system comprising:

• a main amplifier configured to receive a first portion of a radio frequency (RF) signal at a main input and provide an amplified copy of the first portion of the RF signal at a main output;
• a peaking amplifier configured to be controllably activated to receive a second portion of the RF signal at a peak input and provide an amplified copy of the second portion of the RF signal at a peak output;
• and
• a saturation detector having a detector input coupled to the main output of the main amplifier and a first detector control output, wherein the saturation detector is configured to detect saturation of the main amplifier and activate the peaking amplifier as saturation of the main amplifier is detected and deactivate the peaking amplifier when saturation of the main amplifier is not detected by the saturation detector;
• and
• a digital predistortion processor configured to provide digital predistortion to the RF signal before the first portion of the RF signal is received at the main input and the second portion of the RF signal is received at the peak input.