| 摘要: |
| 针对高速双通道时间交织采样（Time-interleaved Analog-to-Digital Converter,TIADC）系统通道失配的问题，提出了一种后台自适应频域校准技术。该技术采用数字混频+低通滤波技术，将失配镜像点搬移至零频，并形成I/Q复数信号；然后基于信号统计学进行校准系数计算，并利用该系数完成共轭对消校准；最后将校准后信号通过数字混频搬移回原始频率，完成整个校准过程。进一步提出了基于FPGA/ASIC的算法实现电路。经实物测试验证，在6 Gsample/s双通道TIADC系统中，该技术能够优化失配比达33.3 dBc以上，失配优化程度高，同时具有全流水实时后台处理特性，且不需要增加额外系统资源。 |
| 关键词: 时间交织采样（TIADC） 通道失配 自适应频域校准 低通滤波 |
| DOI：10.20079/j.issn.1001-893x.220331002 |
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| 基金项目:江苏省高等学校自然科学研究项目（19KJB510027）；江苏省“333工程”科研资助项目计划（BRA2020318）；江苏省专用集成电路设计重点实验室开发基金资助项目（2020KLOP005）；江苏信息职业技术学院科研课题（JKYLX2019-12-205928） |
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| Background adaptive frequency calibration technology for TIADC systems |
| DING Sheng,SUN Youli |
| (1.School of Microelectronics,Jiangsu Vocational College of Information Technology,Wuxi 214153,China;2.Jiangsu Key Laboratoryof ASIC DesignWuxi,Wuxi 214153,China;3.Wuxi Tianchen Jiahang Technology Co.,Ltd.,Wuxi 214000,China) |
| Abstract: |
| For the problem of channel mismatch with dual-channel time-interleaved analog-to-digital converter(TIADC) system,a background adaptive frequency calibration technique is proposed.This method uses moves the mirror point to zero frequency point and forms I/Q complex signal with digital mixing + low-pass filtering technology.Then the calibration coefficient is calculated based on signal statistics and used to complete the conjugate cancellation calibration.Finally,the calibrated signal is moved back to the original frequency by digital mixing technology to complete the whole calibration process.An algorithm implementation circuit based on FPGA / ASIC is proposed.The physical test with dual-channel 6 Gsample/s TIADC system shows this method can enhance the replica rejection ratio up to 33.3 dBc.The method has high degree of optimization for replica rejection ratio,adapts to full pipeline real-time background adaptive processing,and requires no more additional resources. |
| Key words: time-interleaved ADC(TIADC) channel mismatch adaptive frequency calibration low-pass filtering |
