Research On8PSK Identification In HF Communication System

As an important part of the communication signal analysis, the automatic identification technology of communication signal modulation is of a high practical value. In the military areas, it can be used in the electronic surveillance and electronic jamming, in the civilian areas, it can be used in the effective management of the radio spectrum and monitoring of the civil signal transmission. In HF communication, in order to identify the2G-ALE link signal (8FSK) and the3G-ALE link signal (8PSK) quickly and efficiently and switch the working mode of HF communication, it is required to identify the link modulation signal.Based on HF communication, modulation idetification technology of8PSK is mainly discussed in this thesis. Firstly, based on the characteristics in the time domain and frequency domain of some digital modulation signals commonly used (such as ASK, FSK,MSK, BPSK, QPSK,8PSK,16QAM,16QAMstar, π/4QPSK, the two common interferences voice and noise) and general identification methods that decision theory and high-order cumulant, a new3-step identification method is given to identify8PSK from the11kinds of digital signals mentioned above. Simulation result shows that this method is effective. Secondly, in view of the problem that the modulation function of link signal in2G-ALE(8FSK) and3G-ALE(8PSK) is different, based on decision theory and the spectrum of the link signal, some new characteristic parameters are derived and a new2-step identification method is given to identify8FSK and8PSK. This method is implemented in HF communication system which is based on DSP chip TMS320C6713B.