A New Estimation Method of Power Amplifier´s Amplitude and Phase Errors for Adaptive Linearizer using Analog Circuitry

Many linearization techniques for RF power amplifer (PA) need an adaptive control system for tracking drifts of the amplifier´s characteristics and maintaining the performance. To do so, the output distortion or error levels should be monitored constantly. In this paper, we present a new method for estimating the PA´s amplitude and phase errors. The proposed method estimates the amplitude and the phase errors separately. Then these two errors are summed for the estimation of the total error. For feasibility of the system, the error surface is measured applying the embodied estimator to a postdistortion linearizer and compared with the third-order intermodulation distortion (IMD3) improvements obtained in the same control range.