Change search
Refine search result
1 - 27 of 27
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Agevik, Niklas
    et al.
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Fransson, Henrik
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Grunell, Henrik
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Jakiel, Patrick
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Lundin, Henrik
    KTH, Superseded Departments, Signals, Sensors and Systems.
    On Loudspeaker Linearization Using Pre-Distortion2004In: European DSP Education & Research Symposium (EDERS), 2004Conference paper (Refereed)
    Abstract [en]

    In this paper we present a system for linearizing the combined output of a stereo amplifier and loudspeaker through pre-distortion. Removal of room cancellation effects is also discussed. The system uses white noise to estimate an FIR model with the Recursive Least Squares algorithm and experiments show that this can significantly improve the linearity of the sound system. We show that the system can be extended with a nonlinear model and that this indeed can be implemented on a TexasInstruments TMS320C6701 DSP with excellent performance.

  • 2.
    De Vito, Luca
    et al.
    Department of Engineering, University of Sannio, 82100 Benevento, Italy.
    Lundin, Henrik
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Rapuano, Sergio
    Department of Engineering, University of Sannio, 82100 Benevento, Italy.
    A bayesian filtering - Approach for calibrating a look-up table used for ADC error correction2005In: Instrumentation and Measurement Technology Conference, 2005. IMTC 2005. Proceedings of the IEEE, IEEE , 2005, Vol. 1, p. 293-297Conference paper (Refereed)
    Abstract [en]

    The paper presents a new method for the correction of non-linearity errors in ADCs. The method has been designed to allow self calibration in systems where an internal signal can be generated, such as base stations for mobile communications. The method has been implemented and tested in simulation on the behavioral model of a commercial ADCs, and on a hardware setup composed by a data acquisition board and a distorting circuit.

  • 3.
    De Vito, Luca
    et al.
    Department of Engineering, University of Sannio, 82100 Benevento, Italy.
    Lundin, Henrik
    KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre. KTH, School of Electrical Engineering (EES), Signal Processing.
    Rapuano, Sergio
    Department of Engineering, University of Sannio, 82100 Benevento, Italy.
    Bayesian calibration of a lookup table for ADC error correction2007In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 56, no 3, p. 873-878Article in journal (Refereed)
    Abstract [en]

    This paper presents a new method for the correction of nonlinearity errors in analog-to-digital converters (ADCs). The method has been designed to allow a self-calibration in systems where an internal signal can be generated, such as base stations for mobile communications. The method has been implemented and tested in simulation on the behavioral model of commercial ADCs and on a hardware setup composed by a data acquisition board and a distorting circuit.

  • 4.
    Lundin, Henrik
    KTH, School of Electrical Engineering (EES), Signal Processing.
    An Introduction to ADC Error Correction2005Report (Other academic)
  • 5.
    Lundin, Henrik
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Characterization and Correction of Analog-to-Digital Converters2005Doctoral thesis, monograph (Other scientific)
    Abstract [en]

    Analog-to-digital conversion and quantization constitute the topic of this thesis. Post-correction of analog-to-digital converters (ADCs) is considered in particular. ADCs usually exhibit non-ideal behavior in practice. These non-idealities spawn distortions in the converters output. Whenever the errors are systematic, it is possible to mitigate them by mapping the output into a corrected value. The work herein is focused on problems associated with post-correction using look-up tables. All results presented are supported by experiments or simulations.

    The first problem considered is characterization of the ADC. This is in fact an estimation problem, where the transfer function of the converter should be determined. This thesis deals with estimation of quantization region midpoints, aided by a reference signal. A novel estimator based on order statistics is proposed, and is shown to have superior performance compared with the sample mean traditionally used.

    The second major area deals with predicting the performance of an ADC after post-correction. A converter with static differential nonlinearities and random input noise is considered. A post-correction is applied, but with limited (fixed-point) resolution in the corrected values. An expression for the signal-to-noise and distortion ratio after post-correction is provided. It is shown that the performance is dependent on the variance of the differential nonlinearity, the variance of the random noise, the resolution of the converter and the precision of the correction values.

    Finally, the problem of addressing, or indexing, the correction look-up table is dealt with. The indexing method determines both the memory requirements of the table and the ability to describe and correct dynamically dependent error effects. The work here is devoted to state-space--type indexing schemes, which determine the index from a number of consecutive samples. There is a tradeoff between table size and dynamics: more samples used for indexing gives a higher dependence on dynamic, but also a larger table. An indexing scheme that uses only a subset of the bits in each sample is proposed. It is shown how the selection of bits can be optimized, and the exemplary results show that a substantial reduction in memory size is possible with only marginal reduction of performance.

  • 6.
    Lundin, Henrik
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Post-Correction of Analog-to-Digital Converters2003Report (Other academic)
    Abstract [en]

    This thesis deals with digital post-correction of analog-to-digital converters (ADCs). The performance of practical ADCs is deteriorated by non-idealities and flaws in the converter. Methods for mitigating these errors by applying digital signal processing to the output of the converter have been proposed in the past. These methods are often referred to as post-correction methods. This work is mainly concerned with post-correction methods based on look-up tables. Practical ADCs often exhibit dynamical error behavior, meaning that the error is dependent on the dynamics of the input signal. In this thesis an extension of previously proposed post-correction methods is proposed. The method uses the present sample in conjunction with a number of past samples to form the table index. In order to reduce the number of index bits, and thereby the size of the table, the method comprises a ‘bit mask’, which selects a subset of the available bits to be used in the index. Evaluations using experimental ADC data show that the proposed method improves the converter performance, but also that the choice of index bits has a significant impact on the outcome of the correction. The incorporation of a bit mask enables an analysis of the effect of different bit masks. The analysis results in a framework for comparing different correction tables. The framework is then applied in an optimization problem. The goal is to find the best allocation of a fixed number of index bits. Two different criterions are applied: minimization of the total harmonic distortion and maximization of the signal-to-noise and distortion ratio. The results of the optimization, performed with experimental data, show that the optimal bit allocation is different depending on which criterion is used. Moreover, the performance of a correction scheme deteriorates only slowly with decreasing table size, if appropriate index bits are selected.

  • 7.
    Lundin, Henrik
    et al.
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Andersson, Tomas
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Skoglund, Mikael
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Händel, Peter
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Analog-to-Digital Converter Error Correction using Frequency Selective Tables2002In: RadioVetenskap och Kommunikation (RVK), 2002, p. 487-490Conference paper (Other academic)
    Abstract [en]

    Error correction for analog-to-digital converters(ADCs) is considered. The frequency-dependent na-ture of ADC errors motivates the proposal of a novel scheme, incorporating look-up table correction andfast frequency estimation. The method is evaluated using experimental converter data, and the performance, measured in SFDR and SINAD, is found tobe superior to that of non frequency-dependent correction methods.

  • 8.
    Lundin, Henrik
    et al.
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Händel, Peter
    KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Look-Up Tables, Dithering and Volterra Series for ADC Improvements2014In: Design, Modeling and Testing of Data Converters / [ed] Carbone, Paolo and Kiaei, Sayfe and Xu, Fang, Berlin Heidelberg: Springer Berlin/Heidelberg, 2014, p. 249-275Chapter in book (Refereed)
    Abstract [en]

    This chapter gives an introduction and an overview to correction methods for analog-to-digital converters (ADCs), including methods that are implemented using look-up tables, the method known as dithering, and methods that are based on a mathematical model of the ADC.

  • 9. Lundin, Henrik
    et al.
    Händel, Peter
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Skoglund, Mikael
    KTH, School of Electrical Engineering (EES), Communication Theory.
    Accurate prediction of analog-to-digital converter performance after post-correction2006In: 18th IMEKO World Congress 2006: Metrology for a Sustainable Development, 2006, p. 1002-1007Conference paper (Other academic)
    Abstract [en]

    Analog-to-digital converter additive post-correction using look-up-tables is considered. An accurate expression is provided that predicts the ADC performance after correction. The expression depends on differential nonlinearity, random noise variance, and the numerical precisionof the correction terms. The theory shows good agreement when compared with simulations and experimental converter data.

  • 10.
    Lundin, Henrik
    et al.
    Global IP Solutions.
    Händel, Peter
    KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Skoglund, Mikael
    KTH, School of Electrical Engineering (EES), Communication Theory. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Bounds on the performance of analog-to-digital converter look-up table post-correction2009In: Measurement, ISSN 0263-2241, E-ISSN 1873-412X, Vol. 42, no 8, p. 1164-1175Article in journal (Refereed)
    Abstract [en]

    Analog-to-digital converter additive post-correction using look-up tables is considered. The problem of successfully predicting the converter's performance after correction is treated in particular. An accurate expression is provided that predicts the ADC performance after correction. The expression depends on differential non-linearity, random noise variance, and the numerical precision of the correction terms. The theory shows good agreement when compared with simulations and experimental converter data. The results are useful when designing systems involving ADCs and post-correction, since the performance parameters can be obtained with knowledge of a few ADC intrinsic parameters and the correction system resolution.

  • 11.
    Lundin, Henrik
    et al.
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Skoglund, Mikael
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Händel, Peter
    KTH, Superseded Departments, Signals, Sensors and Systems.
    A criterion for optimizing bit-reduced post-correction of AD converters2004In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 53, no 4, p. 1159-1166Article in journal (Refereed)
    Abstract [en]

    Dynamic digital post-correction of analog-to-digital converters (ADCs) is considered. A generalized dynamic correction method is proposed and a framework for analyzing the related bit allocation problem is derived. Finally, this framework is employed in an optimization problem. The solution to the problem indicates which ADC output bits to use in order to maximize the signal-to-noise and distortion ratio in a post-correction system with a constraint on memory size. The proposed methods are accompanied by exemplary results obtained using experimental ADC data.

  • 12.
    Lundin, Henrik
    et al.
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Skoglund, Mikael
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Händel, Peter
    KTH, Superseded Departments, Signals, Sensors and Systems.
    A Framework for External Dynamic Compensation of AD Converters2002In: Proceedings 7th European Workshop on ADC Modelling and Testing, 2002, p. 135-138Conference paper (Refereed)
    Abstract [en]

    External calibration and compensation of analog-to-digital converters is considered. First, a dynamic correction scheme is proposed to comprise bit-masking. Next, a framework for analyzing the effects of bit-reduced table indexing is derived. This framework is finally applied in an optimization problem for bit allocation in the bit mask of the introduced correction scheme. Both the correction method and the optimization problem are exemplified using experimental ADC data. The results indicate that the considered correction scheme is superior to static schemes, and that the choice of bit mask is of great importance, motivating the analysis framework.

  • 13.
    Lundin, Henrik
    et al.
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Skoglund, Mikael
    KTH, School of Electrical Engineering (EES), Communication Theory.
    Händel, Peter
    KTH, School of Electrical Engineering (EES), Signal Processing.
    ADC Post-Correction Using Limited Resolution Correction Values2005In: Proceedings IMEKO 10th Workshop on ADC Modelling and Testing, 2005, Vol. 2, p. 567-572Conference paper (Other academic)
    Abstract [en]

    Analog-to-digital converter additive post-correction using look-up-tables is considered. In a practical post-correction system, the correction values must be stored using limited (fixed-point) precision. In this paper the effects of limited precision in the correction values is investigated. A theory for approximating the SINAD after correction using fixed-point values is presented. The theory shows good agreement when compared with simulation results.

  • 14.
    Lundin, Henrik
    et al.
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Skoglund, Mikael
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Händel, Peter
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Minimal Total Harmonic Distortion Post-Correction of ADCs2003In: International Workshop on ADC Modelling and Testing, 2003, p. 113-116Conference paper (Refereed)
    Abstract [en]

    Dynamic digital post-correction of AD converters is considered. A generalized dynamic correctionmethod is proposed and a framework for analyzing therelated bit allocation problem is introduced. Finally, thisframework is employed in an optimization problem. Thesolution to the problem indicates which ADC output bitsto use in order to maximize the THD in a post-correctionsystem with a constraint on memory size.The proposed methods are accompanied by exemplaryresults obtained using experimental ADC data.

  • 15.
    Lundin, Henrik
    et al.
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Skoglund, Mikael
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Händel, Peter
    KTH, Superseded Departments, Signals, Sensors and Systems.
    On external calibration of analog-to-digital converters2001In: 2001IEEE Workshop on Statistical Signal Processing Proceedings, NEW YORK: IEEE , 2001, p. 377-380Conference paper (Refereed)
    Abstract [en]

    External calibration and compensation of analog-to-digital converters is considered. Two novel methods are presented. Both methods employ multiple calibration frequencies in order to improve the wide-band performance of the converter. Also, a dynamic table indexing is introduced to further improve the performance. A recursive sine-wave reconstruction filter algorithm is developed for calibration purposes. The proposed methods are evaluated using experimental converter data. Results indicate that the dynamic indexing provides good correction performance, also at frequencies not used during calibration. Thus, wide-band calibration can be achieved.

  • 16.
    Lundin, Henrik
    et al.
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Skoglund, Mikael
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Händel, Peter
    KTH, Superseded Departments, Signals, Sensors and Systems.
    On External Calibration of Analog-to-Digital Converters2001In: IEEE Workshop on Statistical Signal Processing, IEEE , 2001, p. 377-380Conference paper (Refereed)
    Abstract [en]

    External calibration and compensation of analog-to-digital converters is considered. Two novel methods are presented. Both methods employ multiple calibration frequencies in order to improve the wide-band performance of the converter. Also, a dynamic table indexing is introduced to further improve the performance. A recursive sine-wave reconstruction filter algorithm is developed for calibration purposes. The proposed methods are evaluated using experimental converter data. Results indicate that the dynamic indexing provides good correction performance, also at frequencies not used during calibration. Thus, wide-band calibration can be achieved.

  • 17.
    Lundin, Henrik
    et al.
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Skoglund, Mikael
    KTH, School of Electrical Engineering (EES), Communication Theory.
    Händel, Peter
    KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    On the estimation of quantizer reconstruction levels2005In: Instrumentation and Measurement Technology Conference, 2005. IMTC 2005. Proceedings of the IEEE, VDE Verlag GmbH, 2005, Vol. 1, p. 144-149Conference paper (Refereed)
    Abstract [en]

    We consider the problem of estimating the optimal reconstruction levels of a quantizer, such as an analog-to-digital converter. A probabilistic transfer function model is applied for the quantizer. Two different assumptions are made for the transfer function, and an estimator based on order statistics is applied. The estimator turns out to give give better results in terms of mean square error than the commonly applied sample mean. The Cramer-Rao lower bound for the estimation problem is also considered, and simulation results indicate that the derived estimator is asymptotically efficient.

  • 18.
    Lundin, Henrik
    et al.
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Skoglund, Mikael
    KTH, School of Electrical Engineering (EES), Communication Theory.
    Händel, Peter
    KTH, School of Electrical Engineering (EES), Signal Processing.
    On the estimation of quantizer reconstruction levels2006In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 55, no 6, p. 2176-2182Article in journal (Refereed)
    Abstract [en]

    We consider the problem of estimating the optimal reconstruction levels of a fixed quantizer, such as the amplitude quantization part of an analog-to-digital converter. A probabilistic transfer function model is applied for the quantizer. Two different assumptions are made for the transfer function, and an estimator based on order statistics is applied. The estimator turns out to give better results in terms of mean square error than the commonly applied sample mean. The Cramer-Rao lower bound for the estimation problem is also considered, and simulation results indicate that the derived estimator is asymptotically efficient.

  • 19.
    Lundin, Henrik
    et al.
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Skoglund, Mikael
    KTH, School of Electrical Engineering (EES), Communication Theory.
    Händel, Peter
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Optimal index-bit allocation for dynamic post-correction of analog-to-digital converters2005In: IEEE Transactions on Signal Processing, ISSN 1053-587X, E-ISSN 1941-0476, Vol. 53, no 2, p. 660-671Article in journal (Refereed)
    Abstract [en]

    Signal processing methods for digital post-correction of analog-to-digital converters (ADCs) are, considered. ADC errors are in general signal dependent, and in addition, they often exhibit dynamic dependence. A novel dynamic post-correction scheme based on look-up tables is proposed. In order to reduce the table size and, thus, the hardware requirements, bit-masking is, introduced. This. is to limit the length of the table index by deselecting index bits. At this point, the problem of which bits to use arises. A mathematical analysis tool is derived, enabling the allocation of index bits to be analyzed. This analysis tool is applied in two optimization problems, optimizing the total harmonic distortion and the signal-to-noise and distortion ratio, respectively, of a corrected ADC. The correction scheme and the optimization problems are illustrated and exemplified using experimental ADC data. The results show that the proposed correction scheme improves the performance of the ADC. They also indicate that the allocation of index bits has a significant impact on the ADC performance, motivating the analysis tool. Finally, the optimization results show that performance improvements compared with static look-up table correction can be achieved, even at a comparable table size.

  • 20.
    Lundin, Henrik
    et al.
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Skoglund, Mikael
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Händel, Peter
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Optimizing dynamic post-correction of AD converters2003In: IMTC/O3: PROCEEDINGS OF THE 20TH IEEE INSTRUMENTATION AND MEASUREMENT TECHNOLOGY CONFERENCE, VOLS 1 AND 2, 2003, p. 1206-1211Conference paper (Refereed)
    Abstract [en]

    Dynamic digital post-correction of AD converters is considered A generalized dynamic correction method is proposed and a framework for analyzing the related bit allocation problem is derived Finally, this framework is employed in an optimization problem. The solution to the problem indicates which ADC output bits to use in order to maximize the SINAD in a post-correction system with a constraint on memory size. The proposed methods are accompanied by exemplary results obtained using experimental ADC data.

  • 21.
    Lundin, Henrik
    et al.
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Skoglund, Mikael
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Händel, Peter
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Optimizing Dynamic Post-Correction of AD Converters2003In: Proceedings IEEE Instrumentation And Measurement Technology Conference, IEEE , 2003, p. 1206-1211Conference paper (Refereed)
    Abstract [en]

    Dynamic digital post-correction of AD converters is considered. A generalized dynamic correction method is proposed and a framework for analyzing the related bit allocation problem is derived. Finally, this framework is employed in an optimization problem. The solution to the problem indicates which ADC output bits to use in order to maximize the SINAD in a post-correction system with a constraint on memory size. The proposed methods are accompanied by exemplary results obtained using experimental ADC data.

  • 22.
    Lundin, Henrik
    et al.
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Skoglund, Mikael
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Händel, Peter
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Post-Correction of Analog-to-Digital Converters2003In: Proceedings Northern Lights Workshop on Sensors, Signals and Systems, 2003Conference paper (Other academic)
  • 23.
    Lundin, Henrik
    et al.
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Skoglund, Mikael
    KTH, School of Electrical Engineering (EES), Communication Theory.
    Händel, Peter
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Signal Processing Results on Dynamic ADC Post-Correction2005In: Proceedings of GigaHertz, 2005Conference paper (Refereed)
    Abstract [en]

    —In this paper we give a brief introduction to some issues and results regarding ADC post-correction. The emphasis is on signal process-ing aspects of post-correction, including dynamics, estimation and round-off effects.

  • 24.
    Lundin, Henrik
    et al.
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Svedman, Patrick
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Zhang, Xi
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Skoglund, Mikael
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Händel, Peter
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Zetterberg, Per
    KTH, Superseded Departments, Signals, Sensors and Systems.
    ADC imperfections in multiple antenna wireless systems - An experimental study2004In: 9th IMEKO Workshop on ADC Modeling and Testing, IWADC 2004, Held Together with the 13th IMEKO TC4 Symposium on Measurements for Research and Industrial Applications, IMEKO-International Measurement Federation Secretariat , 2004, p. 84-89Conference paper (Refereed)
    Abstract [en]

    This paper investigates some of the effects that ADC imperfections may have on wireless communication systems. First, an experimental communication system for wireless multiple-input multiple-output (MIMO) is described. In this test bed, an ADC behavioural model has been implemented. The resulting performance of the communication system, in terms of bit error rate, is assessed when the parameters of the ADC model are altered. The results show that, for this system, the ADC resolution is the key parameter while the non-linearity errors are of minor importance.

  • 25.
    Zetterberg, Per
    et al.
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Jaldén, Joakim
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Lundin, Henrik
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Samuelsson, David
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Svedman, Patrick
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Zhang, Xi
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Implementation of SM and RxTxIR on a DSP-Based Wireless MIMO Test-Bed2004In: Proceedings of the European DSP Education and Research Symposium EDERS, 2004Conference paper (Refereed)
    Abstract [en]

    In this paper we describe the implementation of two smart-antenna strategies and associated signal processing algorithms on a common DSP-based wireless MIMO test-bed. The test-bed supports single cell and two-cell configurations. All nodes (MS andBS) have two antennas (either two transmit or tworeceive) and there are feedback links (via cable) from the receivers to all transmitters.These possibilities has been utilized differently in the two techniques: spatial multiplexing (SM) and joint receiver transmitter and interference rejection (RxTxIR).The SM technique targets a single-link low-mobility scenario and boosts throughput using two parallel spatially multiplexed modulation streams. The RxTxIR scheme utilizes the two-cell configuration of the testbed to demonstrate the possibility of suppressing intercell interference in transmitter as well as the receiver beamforming.

  • 26.
    Zhang, Guoqiang
    et al.
    KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Lundin, Henrik
    KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Kleijn, W. Bastiaan
    KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Band control policy of playout scheduling for voice over IP2008In: Proceedings European Signal Processing Conference, 2008Conference paper (Refereed)
    Abstract [en]

    We study adaptive-playout scheduling for VoIP using the framework of stochastic impulse control theory. A Wiener process is introduced to model the fluctuation of the buffer length in the absence of control. In this context, the control signal consists of length units that correspond to inserting or dropping a pitch cycle. We define an optimality criterion that has an adjustable trade-off between average buffing delay and average control length (the length of the pitch cycles added plus the length of the pitch cycles dropped). The clock-drift effect is treated in a unified manner within this framework. A band control policy is shown to be optimal. The algorithm does not require knowledge of the clock drift. It maintains the buffer length within a band region by imposing impulse control (inserted or dropped pitch cycles) whenever the bounds of the band are reached. Our experiments show that the proposed method outperforms a popular reference method.

  • 27.
    Zhang, Xi
    et al.
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Svedman, Patrick
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Lundin, Henrik
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Zetterberg, Per
    KTH, School of Electrical Engineering (EES), Signal Processing.
    Implementation of a smart antenna multiuser algorithm on a DSP-based wireless MIMO test-bed2005In: IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC, 2005, Vol. 1, p. 126-130Conference paper (Refereed)
    Abstract [en]

    This paper describes the implementation and performance of three communication schemes on a DSP-based MIMO test-bed. A multicell scenario with two basestations and two users in the same room is evaluated. Eigenbeamforming with and without interference pre-whitening at both transmitter and receiver is compared with SISO multicell communication. Experimental results show that the gain from using interference pre-whitening is significant. The BER performance of beamforming without intercell interference suppression is only marginally better than single antenna communication. The paper also presents the implementation of synchronization, equalization, frequency offset estimation and decision directed beamforming mismatch compensation.

1 - 27 of 27
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf