Recalibration of envelope tracking transfer function during active transmission

摘要

An envelope tracking system and a method for adjusting a nonlinear transfer function of an envelope tracking power supply for a power amplifier are provided. An output signal of the power amplifier is provided to a feedback receiver for determining an actual performance of the envelope tracking power amplifier. An assumed performance of the envelope tracking power amplifier is determined by evaluating the non-linear transfer function at a value defined by an input signal for a transmitter including the power amplifier. A difference between the assumed performance and the actual performance provides a correctional value for the nonlinear transfer function.

主权项

1. A method for adjusting a nonlinear transfer function of an envelope tracking power supply for a power amplifier, comprising:
supplying an output signal of the power amplifier to a feedback receiver to obtain a feedback signal; determining an assumed performance of the power amplifier by evaluating the nonlinear transfer function at a first value defined by an input signal for a transmitter comprising the power amplifier; determining an actual performance of the power amplifier by evaluating the nonlinear transfer function at a second value defined by the feedback signal, wherein determining the actual performance comprises:
determining a total gain of the transmitter based on the feedback signal and the input signal; anddetermining an actual gain of the power amplifier based on the total gain and a known gain of the transmitter without the power amplifier, wherein the actual gain is compared with a desired gain of the power amplifier for a given supply voltage for the Power amplifier; and determining a correctional value for a parameter of the nonlinear transfer function based on a difference between the assumed performance and the actual performance.