Wind Profiler Radar Digital If System Design

Radar digital intermediate frequency (DIF) system is designed for meeting the high performance index of Radar receiver. The radar system performance is improved through both high performance acquisition module which make radar intermediate frequency signal to digital directly and advanced digital signal processing by which obtain a bigger linear dynamic range and ideal I/Q data quality. At the same time, it leads the update work to the direction of fast and low cost. From the point of solving the engineer application, a structure of wind profile radar receiver based on band-pass sampling and IF is introduced in this dissertation. Centering on the digital realization, some works have been done in this dissertation as following.At first, the parameter of digital receiver system was confirmed according to the receiver signal character and the system working parameter request. Digital IF system was divided into digital down-converter (DDC), timer and data processing board. The overall design scheme was given out in this dissertation. Secondly, some researches of digital frequency down-convert about input signal had been done. And paying more attention to the IF sampling of digital frequency down-converter, sampling clock and the orthogonal demodulation module with configurable FPGA design parameters. In order to enlarge the dynamic range of radar receiver, an improved saturation compensation algorithm was introduced in this dissertation, and the dynamic range of radar receiver had been improved a lot by introducing this algorithm into digital down-converter. Thirdly, both the timer which produces radar signal and PCI data processing board which used in command analysis and data processing were designed with FPGA.As experiment results, this system successfully accomplished the receiving of intermediate frequency signal, orthogonal demodulation and data processing. At the end, the test results and practical application of radar system were given, which showed that this intermediate frequency system working well and meets the system requirment.