Computer simulation of nonlinear effects of RF power amplifiers based on EVM and ACPR for digital wireless communications

A computer simulation scheme of the error vector magnitude (EVM) and the adjacent channel power ratio (ACPR) of RF power amplifiers (PAs) for digital wireless communications is presented. By using digital signal processing techniques and a time-domain approach, the EVM and ACPR related to the input power can be accurately predicted. The nonlinear effects of the MMIC PA are modelled as the traditional nonlinearity parameter, the third-order intercept point (IP3), which is used to simulate the EVM and ACPR. A computer simulation based on π/4-DQPSK modulation with a square-root raised cosine (SRRC) filter was carried out for this study. A standard NADC modulated signal from an HP ESG-D E4433B signal generator was applied to the PA and the output signal analysed by an HP 89410A vector signal analyser. The measured data agree well with the simulation results