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| 2. |
- Elbornsson, Jonas, et al.
(author)
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Amplitude and Gain Error Influence on Time Error Estimation Algorithm for Time Interleaved A/D Converter System
- 2001
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Reports (other academic/artistic)abstract
- A method for blind estimation of static time errors in time interleaved A/D converters is investigated. The method assumes tha tamplitude and gain errors are removed before the time error estimation. Even if the amplitude and gain errors are estimated and removed, there will be small errors left. In this paper, we investigate how the amplitude and gain errors influence the time error estimation performance.
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| 3. |
- Elbornsson, Jonas, 1975-, et al.
(author)
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Amplitude and Gain Error Influence on Time Error Estimation Algorithm for Time Interleaved A/D Converter System
- 2002
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In: Proceedings of the 2002 IEEE International Conference on Acoustics, Speech and Signal Processing. - 0780374029 ; , s. 1281-
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Conference paper (peer-reviewed)abstract
- A method for blind estimation of static time errors in time interleaved A/D converters is investigated. The method assumes tha tamplitude and gain errors are removed before the time error estimation. Even if the amplitude and gain errors are estimated and removed, there will be small errors left. In this paper, we investigate how the amplitude and gain errors influence the time error estimation performance.
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| 4. |
- Elbornsson, Jonas
(author)
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Analysis, Estimation and Compensation of Mismatch Effects in A/D Converters
- 2003
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Doctoral thesis (other academic/artistic)abstract
- The trend in modern communication systems is to replace as much analog circuits as possible with digital ones, to decrease size, energy consumption and cost. An analog to digital converter (ADC) is the interface between the analog and digital parts. Replacing analog parts, such as mixers, with digital ones requires higher sampling rates. The bottleneck in a digital communication system is often the ADC. Requirements on low power consumption, small chip area and high sample rates are often contradictory to requirements on high accuracy in the manufacturing process.The traditional way to improve the accuracy is to calibrate the ADC before use. However, calibration is time consuming and costly. Furthermore, the errors usually change during the lifetime of the ADC due to, for instance, temperature variation and aging. This means that the ADC must be recalibrated at regular intervals.In this thesis, we investigate how the errors in an ADC can be estimated and compensated for while the ADC is used. The estimation must then be done without any special calibration signal. Two different types of errors are discussed in this thesis. The first type of error is static errors in the reference levels, caused by resistor mismatch. Two methods are proposed for estimation and correction of these errors. The most general method requires only that the amplitude distribution is smooth, while the other one requires knowledge of the amplitude distribution of the input signal butgives a little better performance.The second type of error occurs in time interleaved ADCs, where several ADCs are used in parallel. Due to component mismatch, three different static errors appear: Time errors (static jitter), amplitude offset errors and gain errors. A method for estimation and compensation of these errors is proposed. The method requires basically only that the input signal is band limited to the Nyquist frequency for the system.Another way to decrease the impact of the mismatch errors in a time interleaved ADC is to randomize the selection of which order the ADCs should be used. This randomization spreads the distortion to a more noise like shape. How the mismatcherrors aect the spectrum of a randomly interleaved ADC is also analyzed in this thesis.To confirm that the analysis and estimation methods work in practise the methods are evaluated on both simulated data and data from real ADCs.
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| 5. |
- Elbornsson, Jonas, et al.
(author)
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Analysis of Mismatch Effects in Randomly Interleaved A/D Converter System
- 2003
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Reports (other academic/artistic)abstract
- To significantly increase the sampling rate of an A/D converter (ADC), a time interleaved ADC system is a good option. The drawback of a time interleaved ADC system is that the ADCs are not exactly identical due to errors in the manufacturing process. This means that time, gain and offset mismatch errors are introduced in the ADC system. These errors cause non harmonic distortion in the sampled signal. One way to decrease the impact of the mismatch errors is to spread the distortion over a wider frequency range by randomizing the order in which the ADCs are used in the interleaved structure. In this paper we analyze how the spectrum is affected by mismatch errors in a randomly interleaved ADC system. We also discuss how the mismatch errors can be estimated.
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| 6. |
- Elbornsson, Jonas, et al.
(author)
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Analysis of Mismatch Effects in Randomly Interleaved A/D Converter System
- 2005
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In: IEEE Transactions on Circuits And Systems Part I. - : Institute of Electrical and Electronics Engineers (IEEE). - 1057-7122 .- 1558-1268. ; 52:3, s. 465-476
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Journal article (peer-reviewed)abstract
- To significantly increase the sampling rate of an A/D converter (ADC), a time interleaved ADC system is a good option. The drawback of a time interleaved ADC system is that the ADCs are not exactly identical due to errors in the manufacturing process. This means that time, gain and offset mismatch errors are introduced in the ADC system. These errors cause non harmonic distortion in the sampled signal. One way to decrease the impact of the mismatch errors is to spread the distortion over a wider frequency range by randomizing the order in which the ADCs are used in the interleaved structure. In this paper we analyze how the spectrum is affected by mismatch errors in a randomly interleaved ADC system. We also discuss how the mismatch errors can be estimated.
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| 7. |
- Elbornsson, Jonas, et al.
(author)
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Analysis of Mismatch Noise in Randomly Interleaved ADC Systems
- 2003
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In: Proceedings of the 2003 IEEE International Conference on Acoustics, Speech and Signal Processing. - 0780376633 ; , s. 277-280 vol.6
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Conference paper (peer-reviewed)abstract
- Time interleaved A/D converters (ADC) can be used to increase the sample rate of an ADC system. However, a problem with time interleaved ADC is that distortion is introduced in the output signal due to various mismatch errors between the ADC. One way to decrease the impact of the mismatch errors is to introduce additional ADC in the interleaved structure and randomly select an ADC at each sample instance. The periodicity of the errors is then removed and the spurious distortion is changed to a more noiselike distortion, spread over the whole spectrum. In this paper, a probabilistic model of the randomly interleaved ADC system is presented. The noise spectrum caused by gain errors is also analyzed.
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| 8. |
- Elbornsson, Jonas, et al.
(author)
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Blind Adaptive Equalization of Mismatch Errors in Time Interleaved A/D Converter System
- 2003
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Reports (other academic/artistic)abstract
- To significantly increase the sampling rate of an AID converter (ADC), a time-interleaved ADC system is a good option. The drawback of a time-interleaved ADC system is that the ADCs are not exactly identical due to errors in the manufacturing process. This means that time, gain, and offset mismatch errors are introduced in the ADC system. These errors cause distortion in the sampled signal. In this paper, we present a method for estimation and compensation of the mismatch errors. The estimation method requires no knowledge about the input signal except that it should be bandlimited to the Nyquist frequency for the complete ADC system. This means that the errors can be estimated while the ADC is running. The method is also adaptive to slow changes in the mismatch errors. The estimation method has been validated with simulations and measurements from a time-interleaved ADC system.
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| 9. |
- Elbornsson, Jonas, et al.
(author)
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Blind Adaptive Equalization of Mismatch Errors in Time Interleaved A/D Converter System
- 2004
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In: IEEE Transactions on Circuits And Systems Part I. - 1057-7122 .- 1558-1268. ; 51:1, s. 151-158
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Journal article (peer-reviewed)abstract
- To significantly increase the sampling rate of an AID converter (ADC), a time-interleaved ADC system is a good option. The drawback of a time-interleaved ADC system is that the ADCs are not exactly identical due to errors in the manufacturing process. This means that time, gain, and offset mismatch errors are introduced in the ADC system. These errors cause distortion in the sampled signal. In this paper, we present a method for estimation and compensation of the mismatch errors. The estimation method requires no knowledge about the input signal except that it should be bandlimited to the Nyquist frequency for the complete ADC system. This means that the errors can be estimated while the ADC is running. The method is also adaptive to slow changes in the mismatch errors. The estimation method has been validated with simulations and measurements from a time-interleaved ADC system.
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| 10. |
- Elbornsson, Jonas
(author)
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Blind Equalization of Static Nonlinearities in SA-ADC
- 2001
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In: Proceedings of the Third Conference on Computer Science and Systems Engineering. - Linköping : Linköping University Electronic Press. ; , s. 119-125
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Conference paper (other academic/artistic)abstract
- Due to imperfections in the manufacturing process of integrated A/D converters, there are static non-linear errors in the conversion from analog to digital signal. Calibration of these errors is time-consuming and expensive. In this paper a method for blind equlization of the errors is presented, i.e. the errors are estimated from the output signal only. The method has also been evaluated, with some modications, on measurements from a real A/D converter
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