一种射频信号相位差校准方法及系统实现

A phase difference calibration method for radio frequency signal and a system implementation

通信系统中通道材料和环境会对射频信号的相位产生影响,针对传统相位校准方法存在校准频率低、误差大的问题,提出了一种基于软件无线电技术的相位差校准方法。利用快速傅里叶变换和坐标旋转数字计算机求解频谱最大谱线处的相位值,结合数字正交技术完成信号的相位校准。以亿门级FPGA为核心搭建实验平台对该方法进行了实验测试,利用Xilinx Artix-7产生参考和待校准信号,设计亿门级FPGA的DDR3存储、相位差测量、校准等逻辑电路完成相位差校准。测试结果表明,对于相位差为-90°~90°范围内频率为1 GHz的射频信号,经系统校准后相位差的相对误差小于0.3%,均方根误差仅为0.07°。

Channel materials and environment in communication system will affect the phase of RF signal.Aiming at the problems of low calibration frequency and large error in traditional phase calibration methods,a phase difference calibration method based on software radio technology is proposed.The phase value of the maximum spectral line is solved by the fast Fourier transform and the coordinate rotation digital computer,and the phase calibration of the signal is completed by combining the digital orthogonal technique.The method was tested experimentally with the billion-gate FPGA as the core.Xilinx Artix-7 was used to generate reference and to be calibrated signals,and logic circuits such as DDR3 storage,phase difference measurement and calibration of billion-gate FPGA were designed to complete phase difference calibration.The test results show that the relative error of phase difference is less than 0.3%and the rootmean-square error is only 0.07°for radio frequency signals with a frequency of 1 GHz in the range of-90°to 90°.