Fully Digital Background Calibration Technique for Channel Mismatches in TIADCs

Abstract

Time-interleaved analog-to-digital converter (TIADC) is a promising approach to meet the requirement of very high speed wireless communication systems. However, mismatches between the channels in a TIADC cause the spurious images in the output spectrum, thus decreasing its performance. Therefore, efficient correction techniques for these mismatches are highly required. In this paper, we present a fully digital background calibration technique for channel mismatches including offset, gain and timing mismatches in TIADCs using Hadamard transform and average offset mismatch errors. The proposed technique results in the removal of spurious images from the TIADC output spectrum, thus increases the signal-to-noise-and-distortion ratio (SNDR) and spurious-free dynamic range (SFDR). The performance improvement of TIADCs employing this technique is demonstrated through numerical simulations.