A Study Of Carrier Synchronization Of CPM Signals

As a constant envelope signal, CPM(continuous phase modulation) signal not only can use cheap nonlinear amplifier, but also has a good spectrum characteristics and power efficiency, so it can be used in fading channels and satellite communications. But its applications available are still confined to a few simple forms, such as MSK,GMSK, because of the complexity of Viterbi demodulation algorithms and the difficulties of synchronization. This paper focus on carrier synchronization method of CPM signals. Firstly, the characteristics of CPM signal, phase transfer characteristics and Viterbi algorithm are introduced in detail. Then carrier frequency and phase synchronization algorithms are researched, including data-aided and non dada-aided synchronization algorithm, used for CPM signals with different parameters respectively. This paper introduces the principles of each algorithm, simulates algorithm performance with MATLAB,furthermore analyzes and compares the simulation results. Finally the paper discusses on the practical matter of the data frame structure, and gives brief introductions to the hardware platforms on which CPM modulation and demodulation are implemented, a representative phase synchronous algorithm and the Viterbi algorithm are implemented in this platform.