| 1. |
- Medawar, Samer, et al.
(författare)
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Dynamic Calibration of Undersampled Pipelined ADCs by Frequency Domain Filtering
- 2013
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - 0018-9456 .- 1557-9662. ; 62:7, s. 1882-1891
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Tidskriftsartikel (refereegranskat)abstract
- Integral nonlinearity (INL) is used for the post-correction of pipelineanalog-digital converters (ADC)s. An input-frequency-dependentINL model is developed for the compensation. The model consistsof a static term that is dependent on the ADC output code and adynamic term that has an additional dependence on the input signalfrequency. The INL model is subtracted from thedigital output for post-correction. The static compensationis implemented with a look-up-table (LUT). The dynamic calibration isperformed by a bank of frequency domain filters using an overlap-add structure.Two ADCs of the same type (Analog Devices AD9430) are compensated in the first three Nyquist bands.The performance improvements in terms of spurious-free dynamic range(SFDR) and intermodulation distortion (IMD) are investigated. Using the proposed method, improvements up to 17 dB are reported in favorable scenarios.
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| 2. |
- Medawar, Samer, et al.
(författare)
-
Static Integral Nonlinearity Modeling and Calibration of Measured and Synthetic Pipeline Analog-to-Digital Converters
- 2014
-
Ingår i: IEEE Transactions on Instrumentation and Measurement. - 0018-9456 .- 1557-9662. ; 63:3, s. 502-511
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Tidskriftsartikel (refereegranskat)abstract
- The integral nonlinearity (INL) modeling of pipeline analog-to-digital converters (ADCs) is investigated in this paper. The INL is divided into two distinct entities: a low code frequency (LCF) component and a high code frequency (HCF) component. Two static models are developed to represent the INL data. In both models, the LCF component is represented by a low-order polynomial. The HCF modeling is performed using two different basis functions: sinc and Gaussian. The structure of both HCF models is motivated by the pipeline architecture of the ADC under investigation. The model coefficients are estimated by applying the least-squares method to the measured INL data from two samples of a commercial pipeline ADC. The estimated HCF models are compared to each other and to previous models presented in the existing literature. In addition, the modeling methods are applied to synthetic HCF data generated by a pipeline ADC simulation model constructed in MATLAB. The INL models are then used to calibrate the synthetic ADCs, and the improvements in spurious free dynamic range are compared to those obtained when the ADCs are compensated by the INL data. Furthermore, the capability of the HCF modeling to calibrate a given ADC is tested by using the HCF model to compensate a synthetically generated ADC output in which only the measured HCF sequence and noise are added to the quantization process. The results show that the developed HCF models can achieve virtually complete calibration of the considered ADC.
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| 3. |
- Sundström, Timmy, et al.
(författare)
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Power Dissipation Bounds for High-Speed Nyquist Analog-to-Digital Converters
- 2009
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Ingår i: IEEE Transactions on Circuits and Systems I-Regular Papers. - 1549-8328. ; 56:3, s. 509-518
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Tidskriftsartikel (refereegranskat)abstract
- A very important limitation of high-speed analog-todigital converters (ADCs) is their power dissipation. ADC power dissipation has been examined several times, mostly empirically. In this paper, we present an attempt to estimate a lower bound for the power of ADCs, based on first principles and using pipeline and flash architectures as examples. We find that power dissipation of high-resolution ADCs is bound by noise, whereas technology is the limiting factor for low-resolution devices. Our model assumes the use of digital error correction, but we also study an example on the power penalty due to matching requirements. A comparison with published experimental data indicates that the best ADCs use about 50 times the estimated minimum power. Two published ADCs are used for a more detailed comparison between the minimum bound and todays designs.
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