Study And Realization On Modulation And Demodulation Of Multi-h CPM

The traditional telemetry PCM/FM systems can not meet the requirements,with the increasing complexity of the mission and the emergence of the larger space vehicle,for new space launch vehicles in the future.Multi modulation index continuous phase modulation?Multi-h CPM?,due to its high spectrum and power efficiency,has become the focus of the recent research for the next generation of telemetry systems.The SOQPSK,FQPSK-JR,ARTM CPM,for instance,have been adopted in the IRIG106standard.However,due to the wide variety of Multi-h CPM signals and high complexity of the demodulation algorithm,the Multi-h CPM has been limited to a wider range of applications.Therefore,in the dissertation,the research of the general modulation and demodulation technique of Multi-h CPM signals is researched,in the field of the telemetry.The main contributions are as follows:First of all,the modulation principle of Multi-h CPM signal is presented,and the phase state transition relation under the single-and multi-modulation index is given.It is found that the signal state always has2pM^L-1,if the numerator of multi-modulation index has parity coexistence.And an improved modulation scheme,based on phase generation for Multi-h CPM signals,is proposed,and implemented on the FPGA platform.Secondly,the coherent demodulation algorithm of the Multi-h CPM signal is studied,including the optimal demodulation algorithm of the maximum likelihood sequence detection?MLSD?,and the optimal and suboptimal demodulation algorithms based on PAM decomposition.According to the phase state transition rules of the Multi-h CPM signal,the scheme to construct the multi-state transfer table is proposed,under the phase multi-modulation index,where the table is the core of the demodulator containing all the possible relations between the phase state and transferring path.By comparing the complexity and performance of the three algorithms,it is shown that the PAM suboptimal demodulation algorithm can greatly reduce the complexity of the demodulator with very low performance loss.Finally,the suboptimal PAM demodulation scheme is designed for Multi-h CPM signals,and implemented on the FPGA hardware platform,which includes the matched filter design with four parallel pipeline,the dedicated complex multiplier design based on traverse combination of the look up table,the calculator design of the metric,path and state for the look up table,the Viterbi backtracking design based on shift register,etc.The simulation and test results show the correctness of the Multi-h CPM signal demodulator.