Research And Application Of Wideband Digital Channelized Receiver Based On Double Sub-nyquist Sampling

As an important component of electronic reconnaissance, wideband digital receiver plays a key role in electronic warfare. In order to adapt complex electromagnetism environment, studying digital receiver with high performances such as wideband instantaneous frequency coverage bound, high sensitivity, biggish dynamic range and ability of detecting and processing synchronous signals is an important subject in electronic reconnaissance field.The traditional wideband digital receiver general for zero intermediate frequency signal. But I,Q of digital down conversion have the followed amplitude-phase imbalance negative issues, this will lead to mirror component is difficult to distinguish between the real signal. Meanwhile, it is difficult to detect weak signal, limiting the dynamic range of digital receive. With the rapid development of high-speed ADC sampling technique, the RF signal sampling and processing has become a reality and gradually begin to use. Combined RF signal sampling and digital channelization, this thesis primarily researches and designs the digital channelized receiver, which is based on double sub-Nyquist sampling technology and digital channelized technology. Based o n high-speed ADC and FPGA platform, with the designed short-time Fourier transform(STFT) channelization architecture receiver, the RF signals can be detected and processed by this system. The main works can be summarized as follows:1. The development status of wideband digital channelized receiver is introduced, then based on the principals of signal sampling theorem, multi-rate signal processing and digital filer bank, the realization of digital channelization architecture and wideband digital channelized receiver using sub-Nyquist sampling technique in the time domain is discussed.2. The architecture of digital channelization based on short-time Fourier transform in the frequency domain is analyzed. Then a digital channelization architecture based on double sub-Nyquist sampling in the frequency domain is proposed. The feasibility of the proposed architecture of digital channelization is demonstrated by common radar signals with MATLAB software.3. The platform of ADC and FPGA is constructed based on the principal of digital channelized receiver. The main functional modules of FPGA are designed. The validity of the designed modules are validated and analysed by the Modelsim simulation and the data acquired from engineering test.