A TIADC mismatch calibration method for digital storage oscilloscope
A TIADC mismatch calibration method for digital storage oscilloscope
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DOI：
10.1109/icemi.2017.8265971
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发表时间：
2017-10
期刊：
影响因子：
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通讯作者：
Yang Kuojun;Shi Jiali;Yang Huizhi
中科院分区：
文献类型：
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作者：
Yang Kuojun;Shi Jiali;Yang Huizhi
TIADC（Time Interleaved Analog Digital Converter，时间交错模数转换器）是工程上广泛使用的提高采样率的技术.然而，在TIADC系统中，每个子ADC的失调和增益不相同，并且两个子ADC之间的采样间隔不相等。因此，失配误差在TIADC中是不可避免的，并且会降低系统性能。提出了一种基于统计和FFT分析的TIADC失配误差校正方法。该方法利用统计量得到失调误差，利用FFT估计增益和时间偏移误差。最后，通过在ADC中设置模拟调节元件，对失配误差进行校准。该方法在采样率为5GSPS的基于TIADC的数字存储示波器上得到了验证。实验结果表明，该方法校正失配误差后，信噪比得到了提高，频谱杂散得到了抑制。
TIADC (Time Interleaved Analog Digital Converter) is widely used in engineering to enhance sample rate. However, in TIADC system, the offset and gain of each sub-ADC are not same and sample interval between two sub-ADCs are not equal. Thus, mismatch error is unavoidable in TIADC, and the system performance will be degraded. A method based on statistics and FFT (Fast Fourier Transform) analysis is proposed to calibrate the mismatch error in TIADC. The statistic value is utilized to get offset error, and FFT is used to estimate gain and time skew error. Finally, we calibrate the mismatch error by set the analog adjustment element integrated in ADC. The proposed method is validated in a TIADC based digital storage oscilloscope whose sample rate is 5GSPS. Experiment results show that SNR is enhanced and the spectrum spurs are reduced after mismatch errors are calibrated by proposed method.