Design And Simulation Of Fast Frequency Hopping And High Spread Spectrum Receiver System

In recent years, with the rapid development of science and technology, electronic warfare has gradually dominated in the modern war. In order to effectively avoid enemy's human disturbance and ensure the safety and reliable of the communication process, the information against technology seems more important. Because of the advantages of strong anti-interference, anti multipath fading, low probability of intercept, multiple access communication and high security etc, Direct Sequence spread spectrum/Frequency Hopping hybrid spread spectrum technology has been widely used in military communications and in the field of military technology such as missile guidance. Therefore, how to design a fast frequency hopping, high spread spectrum gain hybrid receiver system is a hot-spot of research on the spread spectrum technology, and it is also the difficulty.Based on the background of "****system" second-period project, this paper mainly research the design of signal structure, the synchronization technology and anti-jamming performance of fast frequency hopping and high spread spectrum gain receiver system. It is also gives an overall design of fast frequency hopping and high spread spectrum gain communication system, which is emulation analyzed by the Matlab/Simulink, the results of simulation show that this system can finish the transmission of signals under the condition of low SNR. Firstly, from the history, current situation and development prospects of spread spectrum technology, this paper mainly studies the mathematical model and working principle of direct sequence spread spectrum, frequency hopping spread spectrum and DS/FH hybrid spread spectrum technology, it also summarizes and analyzes the respective advantages and disadvantages. Then combined with qualifications of fast frequency hopping and high spread spectrum gain receiver system, it finishes the design of signal structure. Then it designs the DS sequence and hopping sequence based on m sequence and R-S sequence, analyzes and simulates the performance of PN sequence. At the same time, this paper studies a carrier modulation way which is more suitable for high jump faster expansion system-code level DQPSK modulation method, analysis and tests its performance.For frequency hopping synchronization, this paper combines synchronization head method and wait-for the search method, which is based on the design of signal structure. It also does the fix-point simulation analysis on Matlab software, and the simulation results verify the effectiveness and reliability of the proposed method. Later, this paper makes some research and analysis on the performance of anti-jamming of the system, mainly including broadband noise interference, narrow-band noise interference, multiple frequency and partial band noise interference, it also analysis and compares the influence of all kinds of human disturbance on the system.Finally, it establishes the overall design scheme of fast frequency hopping and high spread spectrum gain system, and uses Matlab/Simulink platform system for modular modeling and simulation, including the signal source module, the spread spectrum modulation/demodulation module, frequency-hopping modulation/demodulation module and so on. And the correctness and validity of the scheme can be seem from the simulation results. It also provides some guidance for the research and development of fast frequency hopping and high spread spectrum gain system.