Performance of a novel discriminator based quaternary CPM receiver

A novel approach to the design of quaternary continuous phase modulation (CPM) modems, with discriminator detection, is presented. This approach is comparable in complexity to binary modems. The proposed detector yields several dB of signal-to-noise ratio (SNR) savings when compared to the conventional symbol-by-symbol data detector. The numerical results also indicate the superiority of the proposed scheme over binary CPM modems for the same data rate and same bandwidth occupancy. These advantages, however, come at the expense of higher sensitivity to timing errors. Several practical techniques for timing recovery have been tried in the study, and seem to give the desired accuracies