高精度数字鉴相技术的FPGA实现

FPGA Realization of High Precise Digital Phase Discrimination Technology

数字式干涉仪测向采用的是高精度数字鉴相技术,与传统的模拟鉴相技术相比可以大幅度提高鉴相精度,从而满足高精度干涉仪测向的要求。简要分析了数字干涉仪时域鉴相算法,详细阐述了实现高精度数字鉴相技术的关键环节,包括A/D采样,数字下变频设计以及基于坐标旋转数字计算(CORDIC)算法的反正切函数的FPGA实现及优化处理。在Virtex5的vc5sx95t芯片上测试结果表明,可以将数字鉴相误差控制在1°以内。

As compared with traditional analog phase discrimination technology,digital direction finding system of digital interferometer employs high precise digital phase discrimination technology and could thus raise greatly the precision of phase discrimination and satisfy the need of high precise direction finding of interferometer.Based on analysis of phase detection algorithm in time domain,this paper describes in detail the key parts of high precise digital phase discrimination technology,including A/D sampling,digital down convertion design and the FPGA realization and optimized processing of atan function based on CORDIC algorithm.Experiment on vc5sx95t of Virtex5 shows that the error of phase detection is no more than.