Abstract: In a receiver comprising a receiver filter (12) with a frequency attenuation band and a pilot oscillator (25) for generating a pilot oscillation signal with a pilot frequency in the frequency attenuation band, a coupler (26) couples the pilot oscillation signal and a filtered receiver signal of the receiver filter to form a coupled signal. A low noise amplifier (13) amplifies the coupled signal into an amplified signal which comprises an amplified receiver signal component derived from the filtered receiver signal and an amplified pilot oscillation signal component derived from the pilot oscillation signal. A branching filter (27) branches the amplified signal into the amplified receiver signal component and the amplified pilot oscillation signal. A pilot signal component detector unit (28) detects the amplified pilot oscillation signal component to produce a direct pilot signal.

Abstract: In a feed-forward amplifier which has an error detection circuit for detecting a nonlinear distortion component of a main amplifier and an error rejection circuit for amplifying the detected distortion component by an auxiliary amplifier and injecting it into the main amplifier to cancel an error component, a first pilot signal is injected into a signal input path and a second pilot signal is injected into a signal amplification path of the error detection circuit. A first variable attenuator and a first variable phase shifter of the error detection circuit are adjusted by a control circuit so that the level of the first pilot signal component on an error injection path of the error rejection circuit decreases to minimum. A second variable attenuator and a second variable phase shifter of the error rejection circuit are adjusted by the control circuit so that the level of the second pilot signal component on a signal output path decreases to a minimum.