提出了一种基于最小二乘法的时间交替ADC通道失配误差估计方法。将时间交替ADC系统中的某个通道作为参考通道,利用参考通道的输出数据,通过滤波器插值获得非参考通道的理想输出数据。利用最小二乘法分别对非参考通道理想和实际的采样点进行拟合,结合时间交替ADC系统采样模型,对通道失配误差进行估计。仿真表明,即使在测试信号中含有谐波信号以及采样通道存在其他随机误差时,利用该方法仍然能将失配误差的计算准确度控制在±5%以内。最后,通过对实际高速数字化仪通道失配误差的测量证明了该方法的实用性。
Based on least-squares method, this paper presents a new approach for calculating channel mismatch errors of time-interleaved ADC system. Considering one channel as the reference channel, the output samples of the reference channel are interpolated to obtain the ideal samples of the other channels. Using least-squares method, the ideal samples and the actual samples of other channels are fitted by sine wave expressions, which are then combined with the sampling model of the time-interleaved ADC system to calculate the mismatch error of the time-interleaved system. Simulations and experiments demonstrate that the calculation accuracy of this method can be controlled within ±5%, even when there are harmonics in test signal and other random errors in sample channels. Finally, the practicability of the method is verified by the measurement results of channel mismatch errors of a high speed digitizer.