Patent ID: 7126418

Claim:
A feed forward amplifier, comprising: an input for receiving an RF signal; a main amplifier receiving and amplifying said RF signal; a pilot signal source coupled between the RF input and the main amplifier; a main amplifier output sampling coupler; a first delay coupled to the input and providing a delayed RF signal; a carrier cancellation combiner coupling the delayed RF signal to the sampled output from the main amplifier; an error amplifier receiving and amplifying the output of the carrier cancellation combiner; an error coupler combining the output from the error amplifier and the delayed main amplifier output from the second delay so as to cancel distortion introduced by the main amplifier; a phase adjuster coupled between the carrier cancellation combiner and the error amplifier; an output coupled to the error coupler output and providing an amplified RF signal; a pilot signal detector coupled to the output; and an adaptive controller, coupled to the pilot signal detector, for controlling the phase adjuster setting to provide a phase adjustment which is offset from a phase adjustment which minimizes the detected pilot signal, which offset is adjustable by changing the floor of a phase adjustment cost function.