Patent ID: 8605774

Claim:
A method for operating a computer system in order to estimate a time delay that is introduced by an envelope tracking amplifier of a transmitter, wherein the envelope tracking amplifier is configured to receive a first baseband signal that is generated by the transmitter and to operate on the first baseband signal to produce an output signal, the method comprising: utilizing a computer to perform: receiving a second baseband signal from a channel in response to a transmission of the output signal onto the channel, wherein said transmission is performed by the transmitter; generating a model signal that represents an estimate of the first baseband signal by modulating a sequence of information bits; computing a first time delay between an amplitude envelope of the second baseband signal and an amplitude envelope of the model signal; computing a second time delay between a phase signal derived from the second baseband signal and a phase signal derived from the model signal; and estimating the time delay that is introduced by the envelope tracking amplifier of the transmitter by subtracting the second time delay from the first time delay; wherein the estimated time delay is used to program operation of the transmitter.