| CPC H03F 1/3258 (2013.01) [H03F 1/02 (2013.01); H03F 1/0205 (2013.01); H03F 1/0222 (2013.01); H03F 3/19 (2013.01); H03F 3/245 (2013.01); H03F 2200/129 (2013.01); H03F 2200/451 (2013.01)] | 14 Claims | 

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               1. A power amplification system comprising: 
            a power amplifier configured to receive an input signal and provide an amplified signal at an output for transmission through an antenna; 
                a coupler configured to measure forward power from the output of the power amplifier and reverse power including reflected power from the antenna, the coupler including a first port coupled to the output of the power amplifier, a second port coupled to an antenna node for the antenna, a third port for the forward power measurement, and a fourth port for the reverse power measurement; and 
                a controller configured to receive information representative of the measured forward power and reverse power, and based on the information, generate a control signal that includes a signal for providing digital predistortion to a digital signal corresponding to the input signal provided to the power amplifier, the controller further configured to determine load impedance seen by the power amplifier based on the information and adjust either or both of a bias current and a supply voltage for the power amplifier based on the load impedance, the controller configured such that the providing of the digital predistortion and the adjusting of the bias current and/or supply voltage are achieved synchronously. 
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