Estimation method for nonlinearity mismatch in time-interleaved analog-to-digital converters

Abstract

Channel mismatches of time-interleaved analog-to-digital converters (TIADC) would result in significant decline of dynamic performance, especially in signal-to-noise and distortion ratio (SNDR) and spurious-free dynamic range (SFDR). However, as one kind of the channel mismatches, nonlinearity mismatch has not been widely investigated. In this paper, we analyze the characteristics of nonlinearity mismatch and its influence on TIADC's dynamic performance by using polynomial model. A foreground estimation method is proposed and evaluated. The simulation results demonstrate that the proposed method can perform fine estimation accuracy. Furthermore, we investigate the relationship between the estimation accuracy and the sample length, and the result is helpful to configure an appropriate sample length according to different performance requirements.