TI-ADCs非线性误差的多级校正算法研究  

Research of multi-stage correction algorithm for nonlinearity errors in TI-ADCs

作　　者：牛光珊 李雪涛 张建伟 罗向东[1] Niu Guangshan;Li Xuetao;Zhang Jianwei;Luo Xiangdong(School of Information Science and Technology,Nantong University,Nantong 226019,China)

机构地区：[1]南通大学信息科学技术学院,南通226019

出　　处：《电子测量技术》2021年第21期101-107,共7页Electronic Measurement Technology

基　　金：国家自然科学基金重大科研仪器研制项目(61927806)资助。

摘　　要：在分时交替模数转换器(TI-ADCs)系统各项误差的校正中,目前大多方法是针对高速(GSPS)中低精度(≤16 bit)TI-ADCs系统的误差校正算法,且对非线性误差的研究较少,提出了一种适用于高精度(24 bit)TI-ADCs系统的非线性失配误差校正算法。首先提取输入信号经过系统后的含非线性误差输出数据,根据截断的Volterra级数误差模型并借助矩阵变换与最小二乘法(LS)估计出误差系数,然后使用误差重构的多级校正方法来补偿系统的动态非线性误差,得到校正前后的频谱对比图。在单频、多频等频率间隔和不等频率间隔正弦输入情况下进行仿真,四级校正后TI-ADCs系统的SFDR分别由22.91、11.12和11.14 dBc提升到了104.45、96.74和99.25 dBc。结果表明,该方法对TI-ADCs系统的非线性误差在Nyquist频带内的校准在理论上是有效的,对高精度系统校正效果良好。In the correction of various errors of TI-ADCs system,most of the current compensation algorithms are targeted for the errors in high-speed(GSPS) and medium-or-low-precision(≤16 bit) TI-ADCs systems,and there are relatively few researches on nonlinearity errors.A correction algorithm for the dynamic nonlinearity mismatch errors in high-precision(24 bit) TI-ADCs system was proposed.Firstly,the output data containing nonlinearity errors were extracted.Secondly,according to the truncated Volterra series error model,the dynamic nonlinearity errors coefficients were estimated with matrix transformation and LS method.Then,the nonlinearity errors were compensated by a multi-stage correction method based on error reconstruction,and the frequency spectra before and after calibration were obtained.The TI-ADCs system was simulated with single frequency,multi-frequency with equal and unequal frequency interval sinusoidal input,and the SFDR of the system after four-stage calibration was elevated from 22.91,11.12 and 11.14 dBc to 104.45,96.74 and 99.25 dBc,respectively.The theoretical effectiveness of the proposed method in the whole Nyquist band was verified by simulation results,which indicates a calibration effect for high-accuracy system.

关 键 词：分时交替模拟数字转换器 非线性失配误差 VOLTERRA级数 级联校正 

分 类 号：TN792[电子电信—电路与系统]