Patent ID: 7259621

Claim:
A distortion compensating device which is arranged in a previous stage of a power amplifier and compensates for distortion generated in said power amplifier, comprising: a dividing circuit in which an input signal is divided into two and outputted to first and second output terminals; a matching circuit in which a signal from said first output terminal of said dividing circuit is inputted and an impedance is matched; a Field-Effect Transistor in which a source thereof is grounded and a signal from said matching circuit is inputted to a gate thereof; a band pass filter in which a signal from a drain of said Field-Effect Transistor is inputted and only a second harmonic of said input signal is passed; and an addition circuit in which a signal outputted from said band pass filter is added to a signal outputted from said second output terminal of said dividing circuit and said added signal is inputted to said power amplifier; wherein said impedance in said matching circuit affecting a phase of said second harmonic generated from said Field-Effect Transistor is matched so that a distortion component generated in said power amplifier is compensated for by said second harmonic inputted in said addition circuit.