移相器幅相误差对 FFT 法校准误差的影响*

摘要

考虑了快速傅里叶变换（FFT）校准方法在各种配相状态的相关性情况，分析了移相器幅相误差对FFT法校准误差的影响，得到了校准后的幅度误差和相位误差公式。给出了仿真结果，对比仿真结果和理论分析，两者非常吻合。由该公式得出了影响该项误差的因素除了和移相器幅相误差、校准网络的传输系数有关外，还和被校准通道的位置编号有关系。解释了在大动态条件下，校准精度恶化的原因，并给出了解决该问题的方法。%　　The impact of phase shifter amplitude / phase errors on the calibrations based on Fast Fourier Transform (FFT)is analyzed in consideration of the errors correlation. A formula to calculate the errors is given. The analysis and simulation are compared,and the result agrees well. It is shown from the formula that the errors re-late to not only the amplitude / phase errors and calibration network′s S-parameter,but also the serial number of the channel in the FFT method. The reason why the accuracy decreases under the condition of large dynamic range can be found. And a new method which can improve the calibration accuracy is proposed.