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

In time-interleaved (TI) analog-to-digital converters (ADCs), bandwidth mismatches, caused by the limited bandwidth of input signal traces and sample circuits, seriously deteriorate the spurious-free dynamic range (SFDR) of the system. This paper analyzes the influence of bandwidth mismatch errors under different sampling sequences. Eventually, based on a randomization technique and the simulated annealing algorithm (SAA), a bandwidth mismatch optimization technique is presented that can work well with other bandwidth mismatch calibration methods. The behavior simulation results indicate that an improvement of 7[Formula: see text]dB in the SFDR can be achieved with this technique in a 16-channel TI-ADC after timing and gain calibration.

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

2014 IEEE International Symposium on Circuits and Systems (ISCAS) ◽

10.1109/iscas.2014.6865583 ◽

2014 ◽

Cited By ~ 7

Author(s):

Yinan Wang ◽

Hui Xu ◽

Qingjiang Li ◽

Nan Li ◽

Zhaolin Sun

Keyword(s):

Estimation Method ◽

Analog To Digital Converters ◽

Analog To Digital ◽

Time Interleaved

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A Statistic-Based Calibration Method for TIADC System

Mathematical Problems in Engineering ◽

10.1155/2015/689869 ◽

2015 ◽

Vol 2015 ◽

pp. 1-9 ◽

Cited By ~ 1

Author(s):

Kuojun Yang ◽

Shulin Tian ◽

Peng Ye ◽

Peng Zhang ◽

Yuanjin Zheng

Keyword(s):

Sampling Rate ◽

Calibration Method ◽

Wide Frequency Range ◽

Accurate Estimation ◽

Analog To Digital ◽

Average Value ◽

Gain Error ◽

Sampling Points ◽

Interleaved Adc ◽

Time Interleaved

Time-interleaved technique is widely used to increase the sampling rate of analog-to-digital converter (ADC). However, the channel mismatches degrade the performance of time-interleaved ADC (TIADC). Therefore, a statistic-based calibration method for TIADC is proposed in this paper. The average value of sampling points is utilized to calculate offset error, and the summation of sampling points is used to calculate gain error. After offset and gain error are obtained, they are calibrated by offset and gain adjustment elements in ADC. Timing skew is calibrated by an iterative method. The product of sampling points of two adjacent subchannels is used as a metric for calibration. The proposed method is employed to calibrate mismatches in a four-channel 5 GS/s TIADC system. Simulation results show that the proposed method can estimate mismatches accurately in a wide frequency range. It is also proved that an accurate estimation can be obtained even if the signal noise ratio (SNR) of input signal is 20 dB. Furthermore, the results obtained from a real four-channel 5 GS/s TIADC system demonstrate the effectiveness of the proposed method. We can see that the spectra spurs due to mismatches have been effectively eliminated after calibration.

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