Based Broadband Polyphase Filtering Ddc And Its Fpga Implementation

The continuous developments of modern radar technology and the consequent more complicated electromagnetic environment have made it crucial to design wideband, digital, multifunctional software electronic reconnaissance equipment. The digital signal processing has drawn wide attentions in the engineering area and provides an idea development mode for electronic reconnaissance system, which is different form the communication system in its wide-band processing. At present, the mismatch between the high-speed data flow of the wideband A/D converter and processing capability of the general DSP hinders the digitization of the electronic reconnaissance system most. On the other hand, the fast developments of micro-electronic technology and the wide applications of FPGA made digital circuit design more effective and afford an available method to resolve the mismatch between high-speed A/D converters and DSP chips. To resolve the mismatch between high-speed A/D converters and DSP chips,a DDC structure based on polyphase decomposition is intoduced,and it is verificated in the text from not only theories deducing but also computer imitatation according to the Software Radio Principle.In the end,a improvement structure with its realize method of hardware is put forward further. Parallel structure of polyphase decomposition and parallel mixer is applied in the DDC circuit,it solves the bottleneck in mixing and increases the handless speed. The partition of the tuning channel according to the digital mixing sequence, and the DDC by means of decimating first, the low-pass filtering and mixing realize efficiently the down-conversion of the variable carrier frequency band-pass signal. An emulation board of full-probability digital receiver is developed to realize the verification cuicut for the implementations of DDC and frequency estimation algorism with FPGA. The COM port is used to change data between the board and the PC. And this emulation board can be easily used to do verification for the...