基于FPGA的多种量化二元数字干涉仪

Design of multi-quantization digital correlator based on FPGA

相关器是综合孔径微波辐射计系统的核心部件。数字相关器集成度高,重量、体积较小,在辐射计的星载应用上具有更多的优势。粗糙的量化引入了量化噪声,使得系统灵敏度降低;高阶量化则会大量增加系统开支。为了研究低阶量化对于辐射计灵敏度的影响,本文利用FPGA设计实现了一个二至八阶量化的多种量化二元数字干涉仪。使用8-bit A/D转换器对信号进行高速采样,并用FPGA实现信号的二次量化和数字相关。该系统的实验结果和理论及仿真结果基本一致,证明该设计正确可行。

Correlators are core components of radiometer.Being highly integrated,with small weight and volume,digital correlators has more advantages on spaceborne application.However,coarse quantization brings extra quantizing noise to the system,reducing its sensitivity;high level of quantization increases the system cost. In this paper,to investigate the effect of low level of quantization on radiometer sensitivity,design and implementation of a multi-quantization digital correlator of two to eight level quantization is presented. High speed 8-bit A/D convertors are used for signal sampling,and the results are re-quantified and correlated in FPGA. The result of the experiment agrees with the theory and simulation,which proves the design is practical.