Characterization of spectral regrowth in microwave amplifiers based on thenonlinear transformation of a complex gaussian process

A statistical technique is presented for the characterization of spectral r egrowth at the output of a nonlinear amplifier driven by a digitally modula ted carrier in a digital radio system. The technique yields an analytical e xpression for the autocorrelation function of the output signal as a functi on of the statistics of the quadrature input signal transformed by a behavi oral model of the amplifier. The amplifier model, a baseband equivalent rep resentation, is derived from a complex radio-frequency envelope model, whic h itself is developed from readily available measured or simulated amplitud e modulation-amplitude modulation and amplitude modulation-phase modulation data. The technique is used in evaluating the spectral regrowth for a CDMA signal.