Patent ID: 7123086
Filing Date: 2006-10-17
Classification: H03F

Abstract:
1. A feed forward amplifier, comprising: an RF input for receiving an RF signal; a main amplifier receiving and amplifying said RF signal; a main amplifier output sampling coupler; a first delay coupled to the RF 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; a second delay coupled to the output of the main amplifier; an error injection 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; an RF output coupled to the error injection coupler output and providing an amplified RF signal; an output sampling coupler for providing a sampled output of the amplified RF signal; and a positive feedback pilot generator circuit for generating a pilot signal from the sampled output of the amplified RF signal and providing the pilot signal to the input of the main amplifier, wherein said positive feedback pilot generator circuit comprises a bandpass power detector for detecting signal components other than said RF input signal and a pilot generator circuit coupled to the bandpass power detector.