Simplified Frame and Symbol Synchronization for 4-CPFSK with h=0.25

This paper examines the problem of rapid frame and symbol synchronization techniques intended particularly for constant envelope modulation formats M-CPFSK with modulation index h=1/M which are used in strictly bandwidth limited narrowband industrial applications. The data aided and non data aided versions of the algorithm based on digital frequency discrimination are discussed and compared against the synchronization techniques found in literature. Sample wise pattern correlation technique for joint frame and symbol synchronization is also studied. With the focus on a practical digital implementation the advantages and disadvantages of the described approaches are discussed