Patent ID: 7715811

Claim:
A transceiver comprising: an amplifying circuit for amplifying an input signal to produce an output signal; an envelope-tracking power supply operable for varying the level of power that is supplied to the amplifying circuit in response to variation of an input signal envelope directed to the power supply, the envelope-tracking power supply having non-linearities in the transfer function of the power supply; a digital signal processing circuit operable for digitally detecting the input signal envelope used by the envelope-tracking power supply to provide the variation of the power supply level to the amplifying circuit; the digital signal processing circuit including an envelope predistortion circuit operable for receiving the input signal envelope and predistorting the input signal envelope to address non-linearities in the transfer function of the power supply before the input signal envelope is directed to the power supply; the digital signal processing circuit having a main signal path coupled to the amplifying circuit, an envelope tracking path coupled to the envelope-tracking power supply and an input signal path and feedback signal path each coupled to a portion of the envelope predistortion circuit; the digital signal processing circuit operable for introducing a digital delay into a signal in at least one of the main signal path, envelope tracking path, input signal path and feedback signal path.