Low Complexity Nonuniform Satelite Digital Channelizer Design And Implementation

The onboarding flexible transponder is an important part of the mobile satellite communication system.The digital channelizer has the function of dividing the input satellite link signal into several subchannels,and completing the on-board processing functions such as the exchange between the various channels of the sub signals and the reconstruction of the sub signals,so as to realize the on-board exchange among the users with non-uniform bandwidth.In this thesis,based on the study of the low system resource occupation structure of nonuniform digital channelization,an asymmetric digital channelization structure which can realize nonuniform bandwidth is proposed,which can reduce the system resource occupation and ensure the function and performance index of the original method.The main work of this thesis is as follows:1.The selection of existing filter banks and prototype filters is studied,focusing on half band filter,complex exponential modulation filter bank structure and FRM frequency response masking method.2.An asymmetric digital channelization method which based on FRM frequency response masking technology and half band filter is proposed.The structure can realize the analysis and reconstruction of multiple sub signals under the condition of relatively lower system resource occupation,and lower reconstruction error and narrower transition band are realized on the premise of ensuring the original function of digital channelizer.3.The transmission function of the digital channelization method is derived.Based on the result,the prototype filter that meets the design index is obtained according to the requirements of system resource occupation.The reconstruction performance of the digital channelization structure under different modulation modes and different prototype filter orders is analyzed.It is verified that the improved digital channelization structure is feasible in theory,and is suitable for the system The simulation results show that it is the same as the modulation mode and the possible error caused by the specific hardware implementation.4.According to the improved realization method of Digital Channelization,the FPGA realization of this method is completed,and in the hardware realization,combining the timedomain characteristics of half band filter,a further improvement method is put forward,so as to further reduce the resource occupation of the system,and the function simulation of the whole hardware design is carried out.The simulation results are compared with the theoretical simulation results of MATLAB,and the error obtained is less than that of the system.According to the requirements of the system,the FPGA implementation of the efficient digital channelization structure is completed.By comparing the complexity of the improved digital channelization structure with the existing digital channelization method,it is further verified that the system has the characteristics of lower system resource occupation.