Konrad Jędrzejewski
Warsaw University of Technology
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Featured researches published by Konrad Jędrzejewski.
international conference on signals and electronic systems | 2008
Anatoliy Platonov; Jakub Jasnos; Konrad Jędrzejewski; Lukasz Malkiewicz; Zbigniew Jaworski; Elzbieta Piwowarska; Pawel Studzinski
The paper presents the results of design, implementation and adjusting of the CMOS version of the hardware prototype of new ldquointelligentrdquo cyclic analog-to-digit converter (IC ADC). There are presented the concept of intelligent conversion, main principles of practical implementation, main stages and particularities of design and adjusting the IC ADC.
IEEE Transactions on Instrumentation and Measurement | 1998
Anatoliy Platonov; Jerzy Szabatin; Konrad Jędrzejewski
This paper deals with a problem in optimal synthesis of smart measurement systems. A nonlinear model of the sensor is introduced, and directly applied to the derivation of optimal algorithms for processing measurement data. The analysis is performed for systems with both noncompensatory and compensatory sensors. It is assumed that a measurement is performed in the presence of random disturbances and noise. The algorithms developed take into account the limited input-output range of the sensor as well as the influence of its internal noise on measurement quality. Simultaneously, they automatically and optimally correct errors in the initial setting of the sensors working point, as well as those caused by its random drift.
instrumentation and measurement technology conference | 2007
Konrad Jędrzejewski; Anatoliy Platonov
Foundations of a new approach to design and optimisation of pipeline analogue-to-digital converters (PADC) are presented in the paper. The approach employs the results of analytical and applied research on the concurrent optimisation of the analogue and digital parts of adaptive estimation systems. Application of the approach allowed us to modify the known architecture and principles of conversion used in conventional PADC in the way significantly improving quality of conversion. Particularities of new PADC work were studied in advanced simulation experiments, which confirmed the results of analytical investigations. Special attention was paid to comparison of the performance of new and known PADC and assessment of potentially achievable benefits.
international conference on signals and electronic systems | 2012
Konrad Jędrzejewski; Jakub Jasnos
The paper presents a new concept of simplification of the architecture of so called intelligent cyclic A/D converters (IC ADCs) which enables the significant reduction of resolution of a feedback D/A sub-converter. The motivation to work on this problem results from earlier difficulties in design of a precise high-resolution feedback D/A sub-converter in practical implementation of IC ADC in CMOS technology. The modification suggested in the paper simplifies the architecture of IC ADCs and, in consequence, diminishes size, production costs, and power consumption of IC ADCs manufactured as integrated circuits or their parts. Simultaneously, the proposed solution improves the performance of IC ADC and achievable values of effective number of bits.
Photonics Applications in Astronomy, Communications, Industry, and High-Energy Physics Experiments 2012 | 2012
Konrad Jędrzejewski
The paper presents a new approach to improvement of pipeline analog-to-digital (A/D) converters characteristics. The approach is based on application of adaptive estimation algorithms to control and calculate output codes of pipeline A/D converters. Implementation of adaptive algorithms is possible in so called intelligent pipeline A/D converters (IP ADCs) whose digital parts permit to calculate iteratively output codes in form of binary words using simple mathematical operations. This paper develops the earlier research on IP ADCs and removes some disadvantages of conventional IP ADCs simplifying their architecture and increasing achievable values of effective number of bits (ENOB) of converters. Results of selected simulation experiments illustrating new effects related to application of the proposed solutions and their potential benefits are also presented and discussed in the paper.
Symposium on Photonics Applications in Astronomy, Communications, Industry and High-Energy Physics Experiments | 2014
Konrad Jędrzejewski
The paper presents the survey of architectures and conversion algorithms used in so called adaptive analog-to-digital converters considered during the studies on these converters carried out by the author and his colleagues. The key idea that distinguishes the adaptive analog-to-digital converters from other sub-ranging converters consists in application of the iterative digital signal processing algorithm for calculation of the output codes of the converters and for calculation of the values of residue signal gains in subsequent steps of conversion. Application of this approach in the proposed converters allows to achieve better parameters of the converters in comparison with parameters of conventional sub-ranging analog-to-digital converters.
Photonics Applications in Astronomy, Communications, Industry, and High-Energy Physics Experiments 2011 | 2011
Konrad Jędrzejewski
The paper presents a new approach to reduction of influence of disturbances on performance of cyclic analog-to-digital converters (ADC). The approach is based on application of multidimensional estimation algorithms for simultaneous estimation of both input sample value and parameters of disturbances. Implementation of these algorithms is possible in a new class of adaptive cyclic ADCs whose digital parts permit to calculate iteratively output codes in form of binary words using simple mathematical operations. Estimation of parameters of disturbances enables their compensation and elimination of their influence on the conversion performance. Results of selected simulation experiments related to analysis of the efficiency of the proposed method in reduction of disturbances influence on final performance of adaptive cyclic ADCs are also presented and discussed in the paper.
Photonics Applications in Astronomy, Communications, Industry, and High-Energy Physics Experiments 2016 | 2016
Konrad Jędrzejewski; Łukasz Małkiewicz
The paper presents the results of studies pertaining to the influence of gain errors of inter-stage amplifiers on performance of adaptive sub-ranging analog-to-digital converters (ADCs). It focuses on adaptive sub-ranging ADCs with simplified architecture of the analog part – using only one amplifier and a low resolution digital-to-analog converter, that is identical to that of known conventional sub-ranging ADCs. The only difference between adaptive subranging ADCs with simplified architecture and conventional sub-ranging ADCs is the process of determination of output codes of converted samples. The adaptive sub-ranging ADCs calculate the output codes on the basis of sub-codes obtained in particular stages of conversion using an adaptive algorithm. Thanks to application of the optimal adaptive algorithm, adjusted to the parameters of possible components imperfections and internal noises, the adaptive ADCs outperform, in terms of effective resolution per cycle, conventional sub-ranging ADCs forming the output codes using simple lower-level bit operations. Optimization of the conversion algorithm used in adaptive ADCs leads however to high sensitivity of adaptive ADCs performance to the inter-stage gain error. An effective method for reduction of this sensitivity in adaptive sub-ranging ADCs with simplified architecture is proposed and discussed in the paper.
Photonics Applications in Astronomy, Communications, Industry, and High Energy Physics Experiments 2017 | 2017
Konrad Jędrzejewski; Łukasz Małkiewicz
The paper presents a new method for autocalibration of offsets of internal components in adaptive sub-ranging analog-todigital converters (ADCs). The adaptive sub-ranging ADCs, like other iterative ADCs, are very sensitive to offsets caused by technological imperfections. To achieve higher effective resolution in a sub-ranging ADC, offsets should be accordingly diminished, which is achieved using sophisticated techniques usually causing increase of power consumption as well as complexity and size of ADC. But the structure of adaptive sub-ranging ADC and the way of calculation of output codes create a possibility to compensate offsets during conversion of input samples. Moreover, using the internal digital-to-analog converter (DAC) as a source of calibration signal in the procedure of offsets estimation and addition of a calibration program in the digital part of the converter, enable automatization and autonomization (no additional instruments are needed) of the calibration process. Usefulness and limitations of the proposed solution were confirmed in computer simulations whose main results are presented and discussed in the paper. Implementation of the proposed solution enables to increase effective resolution of ADCs and simultaneously to weaken the requirements on acceptable level of offsets of ADC components.
Photonics Applications in Astronomy, Communications, Industry, and High Energy Physics Experiments 2017 | 2017
Szymon Buś; Konrad Jędrzejewski
In this paper, a real-time implementation of pitch shifting with use of phase vocoder algorithm is presented. The goal was to create a system that would allow to process audio signal in real time with use of a general purpose microcontroller. The task was a challenge due to relative complexity of the algorithm and limited computational capacity of the microcontroller, whose architecture is by nature much more universal than that of dedicated digital signal processors. The results of experiments with the developed system are presented and discussed in the paper.