Research And Implementation Of Modulation And Demodulation Technology Of Frequency Hopping Radio

Frequency-hopping(FH)communication with its strong anti-jamming and anti-fading ability,won the favor of the military.Compared with the conventional means of communication,it can strongly safeguard our army to establish stable and reliable voice or data communication,and help our military obtain initiative of information warfare in a war with complex electromagnetic conditions.In addition,FH communication has also been widely used in civil mobile communication,personal communication and so on.The main work of this paper includes three parts.Firstly,a synchronization header format for very high frequency(VHF)FH radio is designed,a synchronization algorithm is proposed for the synchronization scheme,and the algorithm is analyzed theoretically.The implementation steps of the synchronization algorithm are given out,the FH synchronization algorithm is implemented in the hardware.The test results show that the algorithm has a strong anti-interference ability and high sensitivity.Secondly,a joint demodulation algorithm with multiple symbols for the MSK signal is studied,a MSK signal demodulation program is written.The coarse synchronization for FH signals is implemented under low single-noise ratio(SNR).After the coarse synchronization completed,the timing and frequency estimation algorithms aided by data are studied.They are implemented on the hardware which assist the subsequent fine synchronization and demodulation of the data.Thirdly,the timing synchronization algorithm and carrier synchronization algorithm for QPSK signal are studied,.and the complete demodulation process is given out.A QPSK signal demodulation program is written.The fine synchronization and demodulation of the data hops for FH signals are implemented under low SNR.In this paper,the TMS320C6416 DSP chip of TI is used as the main hardware.The paper implement the function of sending and receiving of the VHF FH radio based on DSP,ARM and FPGA.Finally,the performance test is carried out under the requirements,and the result of the test can satisfy the requirement of the project.