An analog linearizer based on amplitude modulation with even harmonic signals

Abstract

In this paper, an analog linearizer using second harmonic signals feedforwarding is proposed. The harmonic generator of the proposed linearizer that consists of a small signal amplifier extracts second harmonic signals. A vector modulator, modulate fundamental signal with second harmonic signals, makes the inverse third order intermodulation distortion (IMD3) signals of power amplifier and controls amplitude/phase of them with modulation factors. As a result, this linearizer is suppressed IMD3 signals of power amplifier effectively. The test results show that IMD3 signals of power amplifier are suppressed more than 20dB for CW two-tone signals. Also, it’s improved the adjacent channel power ratio (ACPR) more than 7dB for CDMA (IS-95) signals.