Patent ID: 7190223
Filing Date: 2007-03-13
Classification: H03F

Abstract:
1. A feedforward amplifier that receives a multicarrier signal, the amplifier comprising: a distortion detection loop in which an input signal is divided into a first route and a second route, wherein in the first route, the phase and amplitude of the input signal are controlled to be amplified, and in the second route, the input signal is delayed, and the signal from the first route is outputted, and the signals outputted from the first and second routes are combined in opposite phase to cancel the fundamental-wave component signals in the input signals and outputted as a distortion component signal; a distortion compensation loop including a third route and a fourth route, wherein in the third route, the signal outputted from the first route is delayed, and in the fourth route, the phase and amplitude of the distortion component signal are controlled to be amplified, and the signals outputted from the third and fourth routes are combined in opposite phase and outputted as an amplified signal; a distortion detecting section that measures the level of the distortion component signal in the fourth route; a receiver that measures the signal level of the adjacent channel leakage power from the amplified signal; an input monitoring section that monitors the input level of the input signal; an output monitoring section that monitors the output level of the output signal; and a controller that controls the phase and amplitude of the input signal in the distortion detection loop and/or the phase and amplitude of the distortion component signal in the distortion compensation loop based on the signal level detected by the distortion detecting section and the receiver, and shifts the position of a frequency at which adjacent channel leakage power is detected depending on the level of the inputted signal or the outputted signal and the signal level measured by the receiver.