Candidate Receivers for Unbalanced QPSK

Abstract

Candidate receivers for unbalanced QPSK signal foremats have been studied. The fourth power receiver is shown to be an unsatisfactory choice unless the power division is close to 50-50 or 100-0. The Costas loop receiver which tracks on the high data rate signal of the unbalanced QPSK waveform is shown to perform satisfactorily. Approximate error rate computations, show that the Costas loop considered performs within a few tenths of a dB of the ideal receiver.