Symbol Synchronization Capture Method on SFH-GMSK - PART I: Signal Analysis

In SFH-GMSK communication, fast and reliable symbol synchronization capture is an important precondition for SFH synchronization and SFH communication. Using the switching-frequency protecting code in SFH data frame, the phase of GMSK signal is particularly studied in this paper. Based on it, the one-bit and two-bit differential demodulation GMSK signal and their phases during protecting codes are especially analyzed. The result shows that the signals and their phases both are periodic, and the period is multiple symbol durations Tb. So they imply the symbol synchronization information, and can be conveniently used in SFH-GMSK signal symbol synchronization capture. Based on this paper (the Part I companion paper) analysis, one symbol synchronization capture method based on signal to noise ratio using switching-frequency protecting code is put forward and analyzed, the result shows this method is very fit for applying in SFH communication in the Part II companion paper.