交错采样技术中的失配误差建模与估计

摘要

Limited by the current manufacturing technique of semiconductor,utilizing a single ADC is unable to meet the re-quirements of high resolution and high sampling rate at the same time.Thus,it is an effective way to achieve high-speed and high-precision sampling by using parallel ADC.Unfortunately,due to the impact of the mismatch errors among the sub-channels,the per-formance of TIADC is greatly reduced.This paper focused on analyzing the sources of various channel mismatches as well as the effects of these mismatches.On this basis,this paper introduced an efficient recognition algorithm for the mismatches.By extracting the distortion spectra in the specific frequency and noticing that the mismatch-harmonic and the error parameters had a relationship of discrete Fourier transform,the actual values of various types of mismatches were got,which provides an effective safeguard for the accuracy of the subsequent error-compensation methods.%受限于目前的半导体制备工艺，单片ADC无法在保证高分辨率的同时满足高采样率的要求，因此利用多片ADC并行阵列的时间交错采样技术是实现高速高精度采样的一种有效方法。但是，受制于各并行通道协同工作时，各路器件的固有差异和信号传输的不一致所带来的失配误差，TIADC（ Time-interleaved ADC）的性能也受到了极大的影响。文中首先分析了各类通道失配误差（包括偏置、增益和时延失配误差）的来源、特征以及它们对TIADC系统性能造成的影响。其次，本文引入一种有效的误差识别算法，通过提取出输出频谱中特定频点处的失真谱线，利用这些失配谐波与误差参数之间互为傅里叶变换对的关系，得到各类失配误差的估算数值，为后续的误差补偿的准确性提供有力的保障。