一种TIADC时间失配误差自适应校准算法

An Adaptive Calibration Algorithm of Time Mismatch Errors for Time-Interleaved ADCs

设计了一种TIADC时间失配误差自适应校准算法。基于相邻通道信号互相关原理,将相邻通道的输出信号作相关运算,利用简单的乘法器、加法器和取绝对值即可实现时间误差的估计;利用基于泰勒级数展开的1阶级联误差补偿方法进行误差校正。误差估计模块和校准模块构成反馈环路,实现误差的实时跟踪与校正。MATLAB仿真结果表明,当输入信号归一化频率为fin/fis=0.477 1时,系统校准后的SNR提高了45dB以上,校准效果明显。相比于传统的基于泰勒级数展开的高阶校准,本文校准算法的结构更简单,校准精度更高,整个奈奎斯特频率范围内均有较好的校准效果,非常适用于工程应用。

An adaptive calibration algorithm of time mismatch errors for time-interleaved ADCs was designed.The method was based on the principle of cross-correlation of the adjacent channel signals,using the output signals of the adjacent channels for the correlation calculation,and using simple multipliers,adders and circuits of taking the absolute value to estimate the time mismatch errors.A 1st cascade error compensation method based on the Taylor series expansion was used to correct the errors.Error estimation module and calibration module formed a feedback loop that could realize real-time tracking and correcting of errors.MATLAB simulation results showed that when the normalized frequency of the input signal was fin/fs=0.477 1,the SNR after calibration was increased by more than 45 dB,so the calibration effect was obvious.Compared with traditional calibration methods based on high-order Taylor series expansion,the proposed calibration algorithm structure was simpler and had a higher calibration accuracy over the entire Nyquist frequency.It＇s suitable for the applications of engineering.