Research On Technologies Of Broadband Digital Channelized Receiver

In the modern electronic battlefield, the electromagnetic environment is filledwith variety of signals. Broadband digital channelized receiver has a largeprocessing bandwidth, high interception probability, and it is considered an idealfrequency measurement receiver in electronic surveillance system. Therefore, thestudy of the digital channelization technology is significant in theory andapplication. The basic filter bank structure is used in traditional channelized receiver,the design is complex and the amount of computation is large. Polyphase structure isused in channelized receiver, which becomes a researching focus in researchinstitutions at home and broad, for its lower computing rate and less computation.In the paper, the implementation of channelization with the basic filter bankstructure is studied, and polyphase filter bank structure is deduced, and detailedanalyzed, based on multi-rate theory and polyphase theory. The impact of transitionbandwidth of the prototype filter and the decimation factor upon receiver isconsidered, the selection of transition bandwidth and decimation factor determinedby mathematical formula is derived to optimize the filter bank design method. Forthe channelization post-processing theory, coordinated rotation digital computer(CORDIC) theory is studied and the method of frequency measurement technologycombined with channel arbitration is studied.MATLAB software is used to simulate polyphase structure of digitalchannelized receiver, and the results of the phase and frequency measurement areanalyzed in the paper. But the frequency resolution of channelized receiver is low,and the frequency of two or more signals arrived at the same time can not bemeasured in a single channel, in response to these shortcoming, a new method isproposed which learns from monobit receiver theory. Good real-time DFT operationis used and overlapped DFT operation is proposed in the new method to realizechannelized receiver. High frequency resolution and good real-time of the newmethod is shown by MATLAB analysis in the system.The complete implementation process of the channelization technology isdesigned in the paper, Quartus Ⅱ software is used to do functional and timingsimulation of the system. According to system’s requirement, modules of system isanalyzed, in which the pulse time of arrival (TOA) and pulse width measurementmodule, polyphase computing module, the IFFT computing module, the CORDICalgorithm extracting amplitude and phase module, the overlapped DFT algorithmare included. The design is optimized and the operation is simplified. The final functional simulation and timing simulation is realized in the same results, thesystem is proved working real-time and correctly.