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Patent Agency Ranking
公开(公告)号：US20170179969A1
公开(公告)日：2017-06-22
申请号：US15365867
申请日：2016-11-30
Applicant: ANALOG DEVICES GLOBAL
Inventor： Qingdong Meng , Hajime Shibata , Richard E. Schreier , Martin Steven McCormick , Yunzhi Dong , Jose Barreiro Silva , Jialin Zhao , Donald W. Paterson , Wenhua W. Yang
Abstract: For continuous-time multi-stage noise shaping analog-to-digital converters (CT MASH ADCs), quantization noise cancellation often requires accurate estimation of transfer functions, e.g., a noise transfer function of the front end modulator and a signal transfer function of the back end modulator. To provide quantization noise cancellation, digital quantization noise cancellation filters adaptively tracks transfer function variations due to integrator gain errors, flash-to-DAC timing errors, as well as the inter-stage gain and timing errors. Tracking the transfer functions is performed through the direct cross-correlation between the injected maximum length linear feedback shift registers (LFSR) sequence and modulator outputs and then corrects these non-ideal effects by accurately modeling the transfer functions with programmable finite impulse response (PFIR) filters.
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公开(公告)号：US09843337B1
公开(公告)日：2017-12-12
申请号：US15460433
申请日：2017-03-16
Applicant: Analog Devices Global
Inventor： Zhao Li , Trevor Clifford Caldwell , David Nelson Alldred , Yunzhi Dong , Prawal Man Shrestha , Jialin Zhao , Hajime Shibata , Victor Kozlov , Richard E. Schreier , Wenhua W. Yang
CPC classification number: H03M1/1023 , H03M1/0673 , H03M1/1009 , H03M1/12 , H03M1/361 , H03M3/384 , H03M3/414
Abstract: Analog-to-digital converters (ADCs) can be used inside ADC architectures, such as delta-sigma ADCs. The error in such internal ADCs can degrade performance. To calibrate the errors in an internal ADC, comparator offsets of the internal ADC can be estimated by computing a mean of each comparator of the internal ADC. Relative differences in the computed means serves as estimates for comparator offsets. If signal paths in the internal ADC are shuffled, the estimation of comparator offsets can be performed in the background without interrupting normal operation. Shuffling of signal paths may introduce systematic measurement errors, which can be measured and reversed to improve the estimation of comparator offsets.
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公开(公告)号：US09912342B2
公开(公告)日：2018-03-06
申请号：US15369175
申请日：2016-12-05
Applicant: Analog Devices Global
Inventor： Zhao Li , Hajime Shibata , Trevor Clifford Caldwell , Yunzhi Dong , Jialin Zhao , Richard E. Schreier , Victor Kozlov , David Nelson Alldred , Prawal Man Shrestha
CPC classification number: H03M1/1009 , H03M1/0626 , H03M1/066 , H03M1/1245 , H03M1/34 , H03M3/388 , H03M3/422
Abstract: An analog-to-digital converter (ADC) is a device that can include a reference shuffler and a loop filter. An ADC can achieve better performance with incremental adjustment of a pointer of the reference shuffler, changing coefficients of the loop filter, and storing calibration codes of the ADC in a non-volatile memory. By incrementally adjusting a pointer of the reference shuffler, a calibration can be performed more efficiently than with a random adjustment of the pointer. By temporarily changing the loop filter coefficients, a greater amount of activity can be introduced into the loop filter. This activity can allow the calibration to proceed more efficiently. By storing the calibration codes in a non-volatile memory, a search space for calibration codes can be reduced. Thus, a calibration can occur more quickly, and the calibration itself can be improved.
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公开(公告)号：US09838031B2
公开(公告)日：2017-12-05
申请号：US15360984
申请日：2016-11-23
Applicant: Analog Devices Global
Inventor： Yunzhi Dong , Hajime Shibata , Trevor Clifford Caldwell , Zhao Li , Jialin Zhao , Jose Barreiro Silva
CPC classification number: H03M3/422 , H03M1/361 , H03M3/322 , H03M3/344 , H03M3/378 , H03M3/388 , H03M3/414 , H03M3/436 , H03M3/464
Abstract: For continuous-time multi-stage noise shaping analog to digital converters (CT MASH ADCs), quantization noise cancellation often requires estimation of transfer functions, e.g., a noise transfer function of the front end modulator. To estimate the noise transfer function, a dither signal can be injected in the front end modulator. However, it is not trivial how the dither signal can be injected, since the dither signal can potentially leak to the back end modulator and cause overall noise degradation. To address some of these issues, the dither signal is injected post the flash analog to digital converter (ADC) of the front end modulator. Furthermore, dummy comparator structures can be used to synchronize the dither with the quantization noise of the targeted flash ADC.
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公开(公告)号：US09768793B2
公开(公告)日：2017-09-19
申请号：US15365867
申请日：2016-11-30
Applicant: ANALOG DEVICES GLOBAL
Inventor： Qingdong Meng , Hajime Shibata , Richard E. Schreier , Martin Steven McCormick , Yunzhi Dong , Jose Barreiro Silva , Jialin Zhao , Donald W. Paterson , Wenhua W. Yang
Abstract: For continuous-time multi-stage noise shaping analog-to-digital converters (CT MASH ADCs), quantization noise cancellation often requires accurate estimation of transfer functions, e.g., a noise transfer function of the front end modulator and a signal transfer function of the back end modulator. To provide quantization noise cancellation, digital quantization noise cancellation filters adaptively tracks transfer function variations due to integrator gain errors, flash-to-DAC timing errors, as well as the inter-stage gain and timing errors. Tracking the transfer functions is performed through the direct cross-correlation between the injected maximum length linear feedback shift registers (LFSR) sequence and modulator outputs and then corrects these non-ideal effects by accurately modeling the transfer functions with programmable finite impulse response (PFIR) filters.
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