适用于TIADC的高精度时间失配误差校准算法

A Highly Accurate Calibration Algorithm in Time Mismatch Errors for Time-Interleaved ADCs

设计了一种适用于TIADC的高精度时间失配误差校准算法。基于相邻通道信号互相关原理,对相邻通道的输出信号作相关运算来估计时间失配误差,再利用基于泰勒级数展开的高阶误差校准方法进行误差校正。误差估计模块与校准模块构成一个反馈环路,可以实现误差的实时跟踪和校正。校准算法行为级仿真结果表明,在12位1GHz四通道的TIADC中,当输入信号归一化频率fin/fs=0.477 1时,校准后系统的ENOB提高到11.85位,SNR提高了43dB以上,校准效果明显。相比已有的校准算法,该校准算法具有更高的校准精度,不受通道数的限制,结构更简单,且在整个奈奎斯特频率范围内都适用,非常适合工程应用。

A highly accurate calibration algorithm in time mismatch errors for time-interleaved ADCs was designed. The algorithm was to estimate the time mismatch error based on the principle of cross-correlation of adjacent channel signals, and a high-order error correction algorithm was used to calibrate the time mismatch error based on Taylor series. Error estimation module and calibration module formed a feedback loop, which could achieve real-time tracking and correcting of error. Through MATLAB simulation, the results showed that for the 12 bit, 1 GHz four-channel TIADC, when the normalized frequency of the input signal fin/f~ was 0. 477 1, and after calibrating, the ENOB was improved to 11.85 bit and the SNR was increased by more than 43 dB, so the calibration effect was obvious. Compared with existing calibration algorithm, the simulation results showed that the proposed algorithm had a higher calibration accuracy and a simpler structure. It was not limited by the number of channels. It was suitable for the applications over the entire Nyquist frequency, especially in engineering applications.