Research On Short - Term Burst PSK Signal Analysis And Blind Demodulation

The application of short-burst signal is growing more and more widely because of its good self-adaptability and anti-jamming property. So it has an important theoretical significance and practical value to research on demodulation technology for short-burst signal. This thesis investigates blind demodulation algorithm for short-burst PSK signal. Symbol rate estimation, carrier frequency offset estimation and timing synchronization are the main subjects. The main tasks and contributions of the thesis are as follows.Firstly, the background and significance of the research on short-burst PSK signal is discussed in the thesis. We introduce the history and current situation about this research at home and abroad. The motivation and content are also explained in this part.Secondly, parameter estimation technology, both symbol rate estimation and carrier frequency offset estimation, is investigated in the thesis. As for symbol rate estimation for short-burst PSK signal, we studies algorithms based on the instantaneous magnitude spectrum, M power spectrum and wavelet transformation. We analyze the drawbacks of the traditional algorithms and give the corresponding improvements. As for carrier frequency offset estimation for short-burst PSK signal, we studies algorithms based on DFT, auto-correlation function and signal phase. Improved algorithms based on interpolation and iterative methods are also introduced. We also propose a new frequency offset estimation algorithm based on PSO in the thesis.Thirdly, timing synchronization technology, both timing error detection and timing error correction, is investigated in the thesis. As for timing error detection, we studies different nonlinear transformation algorithms based on ML criterion, low sampling rate algorithms and timing algorithm in time domain. Interpolation filter is used for timing error correction, which can be implemented in high speed Farrow structure.Fourthly, we present a scheme of burst-mode PSK demodulator and implement it on FPGA platform. The correctness of the algorithm is verified by hardware tests.In the end, we summarize the whole tasks in our research and give some advice on further study in the future.