移相器幅相误差对FFT法校准误差的影响

Impact of Phase Shift Amplitude/Phase Errors on FFT-based Calibrations

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 fannula 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 relate 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.