Patent ID: 7693674
Filing Date: 2010-04-06
Classification: G01R,H03F

Abstract:
1. A system, comprising: a signal source: a first variable amplifier adapted to amplify an output signal from the signal source to provide an amplified signal; a feed-forward amplifier adapted to amplify the amplified signal to provide an amplified output signal; a phase noise measurement system adapted to provide a first feedback signal that is proportional to phase noise in the amplified output signal; and a controller adapted to control the amplification provided by the variable amplifier, the controller being responsive to the first feedback signal so as to minimize the phase noise in the amplified output signal, wherein the feed-forward amplifier includes a VCO controlled to provide a VCO signal having a frequency equaling a frequency of an undesirable signal component in the amplified output signal, the feed-forward amplifier further including a variable phase-shifter and a second variable amplifier to provide a phase-shifted and amplified version of the VCO signal, the feed-forward amplifier further including a coupler to couple the phase-shifted and amplified version of the VCO signal into the amplified output signal, the controller being adapted to control the variable phase-shifter and the second variable amplifier such that the phase-shifted and amplified version of the VCO signal reduces the undesirable signal component.