The Impact of Long Term Memory Effects in Wireless QPSK Modulated Signals

This paper studies the impact of power amplifiers, PA, long term memory effects in QPSK modulated signals. To quantify the memory effects an expansion of the nonlinear distortion behavior of the PA is obtained. Both the co-channel and adjacent distortion are calculated. It is then showed that the co-channel and adjacent channel distortion are significantly affected by the long term memory effects, which implies a rise in the EVM figures. The theoretical results are further compared with CAD/CAE simulations and measurements.