Research And Realization Of G Function And Synchronization Technique In Differential Frequency Hopping Communication System

Differential Frequency Hopping (DFH) has grown up into a new communication technique in these years. Based on the technique of digital signal processing, it can achieve high-powered features, such as high hopping rate and broad hopping band. Compared with conventional Frequency Hopping (FH) techniques, it also shows its outstanding abilities on anti-jamming and anti-fading.First, the concept and generating principle of the G function in DFH system are researched in this paper, using the evaluation method of detecting function capabilities, randomicity and uniformity of DFH sequences generating methods based on chaotic mapping disturbed by m-sequences are examined. Result shows that DFH sequences have better randomicity and uniformity after disturbed.Secondly, parallel-search capturing technology of Differential Frequency Hopping in communications and two typical tracking algorithm are mainly studied. In addition, simulations on validation of early-late gates synchronous tracking methods adopted by hardware platform are given.Finally, intermediate frequency hardware platform is built and typical algorithm is realized on FPGA by using VHDL language.Transmitting and receiving part are included in this platform. The transmitting part includes frame structure design, frequency hopping realization and shortwave channel simulation; the recriving part includes use of FFT unit inside FPGA, realization of synchronization acquisition and tracking of DFH communication system.