Study Of High Speed Shortwave Correlated Frequency Hopping System

Frequency hopping technology has served in all kinds of communication systems with its excellent interference resistance ability, especially in short wave communication system. However, traditional frequency hopping radios have a lot of disadvantages, such as low rate of frequency hopping, low message symbol rate, bad audio quality. The Correlated Frequency Hopping communication technology is a new type of Frequency Hopping technology, which introduces correlation between frequency series. So the system has the characteristics of interference resistance hopping rate and high and fading resistance and can gain high frequency message symbol rate. In this paper, development on High Frequency communications and frequency hopping communications technology are presented firstly, and the disadvantages are pointed out. After introducing the spectrum spread communication technology, the advantages, applications and development of frequency hopping technology are described briefly. Moreover, the principle on the Correlated Frequency hopping technology is expatiated. Compared with the linear transition algorithm, and put forward an improved scheme. The advantages of this improved scheme are pointed out and the key techniques on the Correlated Frequency hopping are introduced. The paper focus research on design of Correlated Frequency Hopping communication system.Signal Design. Transmitted Waveform, Data Frame Structure, Channel Coding, Interleaving Form and Scrambling Form are design in details. The key techniques on the Correlated Frequency hopping are studied and simulations are carried out. Frame synchronizing signal is designed and the signal can detect channel and indicate data transmission rate. The work module of FFT Unit is designed. Optimizing the FFT algorithms and analyzing the value from the optimized algorithms. A demodulation algorithm is designed. An interference suppression algorithm based on signal time domain is put forward and the algorithm can take effect in suppression of constant frequency interference. At last, the paper presents the system implementation scheme based on DSP and designs relevant block diagrams of software and hardware. Presenting and analyzing the simulation result of system performance in the condition of gaussian white noise. Lastly the thesis draws concludes and points out future research directions.