The aim of this paper is the determining the system performance in detecting the QPSK signal. The error probability is determined when the signal, Gaussian noise, pulse interference and imperfect carrier phase recovery are taken into consideration. Phase locked loop, as the constituent part of the receiver, is used in providing the synchronization reference signal extraction, which is assumed to be imperfect. The obtained results are based on the PLL non-linear model of the first order, with the emphasis on the degradation in the system performance produced by the imperfect carrier signal extraction. The system performance is determined when the signal corrupted by pulse interference and Gaussian noise is applied at the input of the receiver.
Performance of qpsk system in the presence of pulse interference and noisy carrier reference signal