Linking nonlinear distortion and a signal’s cumulative distribution function: a measurement-based approach

Driven by societal, economical and technological pressures, wireless transmitters are becoming increasingly complex to achieve high power efficiency. High power efficiency is mainly obtained by pushing the RF power amplifier (PA) further into its nonlinear operating regime, which inevitably increases the nonlinear distortion generated by the amplifier. It is theoretically known that these distortions depend on both the power spectral density (PSD) and the probability density function (PDF) of the modulated excitation signal. In this paper, we experimentally validate the dependency of the nonlinear distortion with the cumulative distribution function (CDF) of the excitation signal’s envelope. First, we propose a novel design strategy that can impose the power spectral density and cumulative distribution function of an IQ-modulated signal. Next, measurements are performed on a nonlinear power amplifier, which experimentally validate the dependence of the amplifier’s linearized behavior on the envelope’s cumulative distribution function.