A calibration method for frequency response mismatches in <i>M</i>-channel time-interleaved analog-to-digital converters

Abstract

Frequency response mismatches (FRMs) in time-interleaved analog-to-digital converters (TIADCs) generate undesired spurs degrading the performance of TIADCs. This paper introduces a digital calibration method for the FRM in M-channel TIADCs (M-TIADCs). This method exploits fixed differentiator finite-impulse response (FIR) filters and the Hadamard transform to reconstruct the mismatch induced error signal. The mismatch parameters are estimated utilizing a short training signal and the least square (LS) method. Our method is simpler in terms of implementation compared with conventional methods as cumbersome time-varying filters, complex signal processing and front-end hardware modifications are avoided. Numerical simulation results demonstrate the efficacy and efficiency of the proposed method. Keywords: frequency response, time-interleaved ADC, mismatch, polynomial representation, Hadamard transform, least square Classification: Circuits and modules for electronic instrumentation

Calibration of static nonlinearity mismatch errors in TIADC based on periodic time-varying adaptive method

“…Unfortunately, the non-ideal effects in the analog building block implementations cause significant performance degradation for TIADC system [6,7]. During the past few decades, the estimation and compensation methods for offset, gain, time, and frequency mismatches are investigated extensively [8][9][10][11][12][13]. In recent years, there has been an increasing interest in nonlinear mismatch problems in TIADC system [14][15][16][17][18][19][20][21][22][23][24][25].…”

Efficient real-time blind calibration for frequency response mismatches in two-channel TI-ADCs

“…These mismatch errors introduce modulated spectral components and degrade the dynamic performance of the overall sampling system, which greatly limit the applicability of TI-ADCs. With the gain, offset and timing mismatch studied thoroughly [4,5], much work has been focused on the calibration of frequency response mismatches [6,7,8,9,10]. In [8], a flexible and scalable frequency response mismatches compensation structure has been proposed.…”

A Calibration Method for Nonlinear Mismatches in M-Channel Time-Interleaved Analog-to-Digital Converters Based on Hadamard Sequences

“…Although Hadamard sequences (Hadamard transforms) are also exploited to deal with the frequency response problem in M-TIADCs [32], there are fundamental differences between these two papers. Firstly, the focus of this paper is the nonlinear mismatch problem, while the focus of [32] is the frequency response mismatch problem; secondly, the method proposed in this paper is totally blind, while the method adopted in [32] requires a training sequence.…”

“…Firstly, the focus of this paper is the nonlinear mismatch problem, while the focus of [32] is the frequency response mismatch problem; secondly, the method proposed in this paper is totally blind, while the method adopted in [32] requires a training sequence.…”