Research And Implementation Of Multi-h CPM Modulation And Demodulation Technology

With the rapid development of space science and application technology,various communication technologies have emerged endlessly,and the aerospace telemetry system has also been continuously improved in accordance with the requirements of the times.Multi-index continuous phase modulation(Multi-h CPM)technology,as a new generation of telemetry system,has gradually appeared in many research fields with the advantages of constant envelope and high bandwidth efficiency and has been further developed.However,due to its own signal characteristics,coupled with the numerous uncertainties of the parameters,and the high complexity of synchronization and demodulation in the receiver design,the process of theoretical research turning into engineering implementation is relatively slow.Therefore,this article focuses on the Multi-h CPM modulation and demodulation technology,and conducts in-depth research on theoretical analysis and engineering applications.The main contents are as follows:First of all,based on the investigation of a large number of literatures,the research background of the subject and the current development status of CPM and Multi-h CPM are introduced,the technical advantages and existing problems are analyzed,and the research significance of Multi-h CPM modulation and demodulation technology is elaborated.The basic concepts and theories related to Multi-h CPM technology are introduced,the power spectrum density is deduced and the influence of each parameter on the signal power spectrum is emphasized.The optimal demodulation model based on the maximum likelihood principle is given,and the sequence detection algorithm is analyzed.Process to pave the way for later research and implementation.Then based on the theoretical analysis of the signal and software radio design ideas,a general Multi-h CPM modulation system based on zero-IF architecture is proposed.The modulation parameters are constructed on the premise of the research background of the subject,and a detailed system design scheme is given.It is implemented on FPGA + AD9364 platform,and the correctness is verified through engineering simulation results and signal spectrum test.Finally,the synchronization and demodulation in the receiver design process are studied in depth,and the related synchronization algorithm process is analyzed and derived,and its performance is compared and improvements are proposed.The PAM decomposition of the Multi-h CPM signal is mainly introduced,the PAM decomposition process is derived in detail,and an optimal demodulation algorithm based on PAM decomposition is given.Based on this,a low-complexity demodulation algorithm based on PAM decomposition is proposed.Verification and analysis of algorithm complexity and bit error performance.Finally,the Multi-h CPM sequence detector is designed,and the proposed low-complexity sequence detection algorithm is verified using Modelsim software,and the bit error rate is calculated to provide a preliminary solution for the engineering implementation of Multi-h CPM signals.