Research And Implementation Of Digitao Channelized Receiver In Passive Radar Seeker

LPI radar and frequency agility radar have brought a great challege for tranditonal receiver of passive radar seeker. In order to receive wideband signals and process multiple simultaneous signals, application of digital channelized receiver in passive radar seeker was studied in this dissertation. The efficient architectures of digital channelized receiver, dynamic channelized receiving technology and channelized subsequent processing technology were primarily researched. A set of digital channelized receiver was designed and realized based on engineering application and the performance of the digital channelized receiver was tested and analyzed.In respect of uniform digital channelized, the frequency band division methods of complex signal and real signal were analyzed and an universal polyphase filter architecture was deduced form low pass filter architecture. According to different frequency band divisions, the various complex signal efficient channelized architectures and real signal efficient channelized architectures were given in different conditions that are critical decimation or non-critical decimation, even alignment or odd alignment. A real signal efficient channelized architecture based on non-aliasing and non-blind area and an efficient channelized architecture based on WOLA were proposed. The calculations of various efficient channelized architectures were compared and analyzed.A digital channelized receiving method, which improved sensitivity of signal sorting channel and provided new sorting parameter, was proposed according to digital channelized application in passive radar seeker. A problem that the outputs of 0th channel have real part and have not image part in real signal even alignment architecture was discussed. A kind of I and Q channels generation method based on Hilbert transform was proposed in order to realize parameter analysis of 0th channel. The implementation method of digital channelized efficient architecture was studied.In respect of dynamic channelized receiving, the efficient dynamic channelized architectures based on DFT and based on WOLA were deduced based on signal reconstruction theory. The two architectures can realize non-uniform channel division and dynamic channelized receiving by estimation of channel to solve the cross-channels problem for wide band signals.In respect of channelized subsequent processing, the CORDIC algorithm was adopted to extract signal envelope and instantaneous phase and the phase difference algorithm was adopted to realize frequency measurement. The phase difference was gotten by instantaneous phases subtracting of two intermediate frequency signals and phase-unwrapping. As sub-channels were wide, it is possible to exist multiple signals in sub-channels. The method of FFT spectral analysis was adopted and the resource occupying of FPGA was evaluated.In respect of system implementation, the high-speed ADC08D1000 of National Semiconductor and the FPGA of ALTERA were adopted to realize a set of digital channelized receiver. The various functions and technical specifications were tested and analyzed in detail and some improved suggestions were proposed.