Patent ID: 6326840
Filing Date: 2001-12-04
Classification: H03F

Abstract:
A feed-forward distortion compensation amplifier having a distortion detecting loop and a distortion compensating loop that are connected in series with each other,wherein in the distortion detecting loop, an input signal is branched into two input signals, one of the branched input signals is amplified by an amplifier whose output signal is branched, such that a branched output signal from the amplifier and the other branched input signal are inverted relative to each other and are combined together to extract a distortion component signal produced by the amplifier, andwherein in the distortion compensating loop, the distortion component signal outputted from the distortion detecting loop and the output signal from the amplifier are inverted relative to each other and are combined together to obtain an amplifier output signal from which the distortion component signal produced by the amplifier has been removed, said feed-forward distortion compensation amplifier comprising:an adjusting means disposed in said distortion detecting loop, for adjusting said branched output signal from the amplifier and said other branched input signal to amplitudes and phases that are inverted relative to each other;a detecting means for detecting the distortion component signal extracted by said distortion detecting loop;a changing means for changing the distortion component signal to a substitute signal having an amplitude smaller than a predetermined threshold if the amplitude of the distortion component signal is greater than the predetermined threshold; andan adjustment control means for controlling said adjusting means based on the amplitudes of the detected distortion component signal and the substitute signal in order to reduce the amplitude of the distortion component signal detected by said detecting means.