Menu
EN

Vyhledávání

Lidé

doc. Ing. Josef Vedral, CSc.

Všechny publikace

Non-destructive diagnostic of high voltage electrical systems

  • Autoři: doc. Ing. Josef Vedral, CSc.,
  • Publikace: Aalborg: River Publishers, 2022. Energy Enginnering and Systems. vol. 1. ISBN 9788770228022.
  • Rok: 2022
  • Pracoviště: Katedra měření
  • Anotace:
    This book describes the methods of signal processing used in the non-destructive diagnostics of mechanical and electrical properties of high-voltage electrical machines. Traditional and less traditional methods are given, which allow measuring the mechanical and electrical properties of these machines in order to determine their technical condition, including a description of their measurement methods. Separate chapters are devoted to the causes and methods of measuring and evaluating partial discharges arising in the insulation systems of high-voltage electrical machines. The following chapters provide an overview of the test methods used in the non-disassembly diagnostics of high-voltage transformers, rotary machines, high-voltage cables, insulators, surge arresters and circuit breakers. The book is intended for students of technical universities and experts in the field of non-destructive diagnostics of high-voltage electrical machines.

Digital measuring instruments of electrical quantities

  • Autoři: doc. Ing. Josef Vedral, CSc.,
  • Publikace: Praha: CTU. Czech Technical University Publishing House, 2021. ISBN 9788001068601.
  • Rok: 2021
  • Pracoviště: Katedra měření
  • Anotace:
    The book describes properties and methods of measuring electrical quantities by digital measuring instruments. In addition to the basic methods of measurement of these quantities, less traditional methods and instruments are presented with the aim of achieving high accuracy and reproducibility of the measurement results. The properties of digital multimeters, calibrators, selective amplifiers, universal counters, impedance meters, signal generators, digital oscilloscopes, spectral and vector analyzers, power meters, inspection and diagnostic instruments and measuring systems are analyzed in detail. The book is intended for students of technical and non-technical universities and all other workers who use electronic digital measuring instruments of electrical quantities in their activities.

Analog Signal Processing and Digitization in Measurement

  • Pracoviště: Katedra měření
  • Anotace:
    The book describes circuit devices and methods of analog signal processing from typical sensors of physical quantities and means for their digitization and reconstruction including description of selected methods of their digital processing. The book is supplemented with practical principles of construction of analog-digital systems in terms of the transmission and isolation of analog signals, the method of printed circuit design, the elimination of interfering signals, the method of power supply and grounding of circuits. It also contains examples of simulations of these circuits in time and frequency domain in MULTISIM program.

Číslicové měřicí přístroje

  • Autoři: doc. Ing. Josef Vedral, CSc.,
  • Publikace: Praha: CTU. Czech Technical University Publishing House, 2020. Odborná kniha. ISBN 978-80-01-06777-2.
  • Rok: 2020
  • Pracoviště: Katedra měření
  • Anotace:
    Kniha popisuje vlastnosti a způsoby měření elektrických veličin číslicovými měřicími přístroji. Mimo základních metod měření těchto veličin jsou uvedeny i metody méně tradiční a přístroje s cílem dosažení vysoké přesnosti a reprodukovatelnosti výsledků měření. Podrobně jsou analyzovány vlastnosti číslicových multimetrů, kalibrátorů, selektivních zesilovačů, univerzálních čítačů, měřičů impedance, signálních generátorů, číslicových osciloskopů, spektrálních a vektorových analyzátorů, měřičů výkonu a elektrické energie, revizních a diagnostických přístrojů a měřicích systémů. Kniha je určena studentům technických i netechnických vysokých škol a všem ostatním pracovníkům, kteří užívají číslicové měřicí přístroje elektrických veličin ve své činnosti.

Experimental Verification of the Fully-Digital High Voltage FPGA-Based Diagnostic Equipment

  • DOI: 10.1109/NTSP49686.2020.9229545
  • Odkaz: https://doi.org/10.1109/NTSP49686.2020.9229545
  • Pracoviště: Katedra měření
  • Anotace:
    This paper discusses the problems of the noninvasive diagnostic of high-voltage machines. The main role of the diagnostic is to predict an upcoming machine failure. Frequency response and frequency domain spectroscopy methods are studied in this paper. The methods are compared in terms of common instrumentation features. A development of a hardware platform intended for both methods is presented. The platform is evaluated in the terms of accuracy and compared with laboratory instrumentation. The results of the evaluation showed the proposed solution is able to implement both methods and have a measurement accuracy comparable with market available instruments implementing only one method

Application of Poly-harmonic Signals to Eddy-current Metal Detectors and to Advanced Classification of Metals

  • DOI: 10.24425/119564
  • Odkaz: https://doi.org/10.24425/119564
  • Pracoviště: Katedra měření
  • Anotace:
    A limited ability to discriminate between different materials is a fundamental problem with all conventional eddy current based metal detectors. This article presents the use, evaluation and classification of non-traditional excitation signals for eddy current metal detectors to improve its detection and discrimination ability. The presented multi-frequency excitation signals are the following: a step sweep sine wave, a linear frequency sweep and sin(x)/x signals. All signals are evaluated in a frequency domain. An amplitude and a phase spectra and polar graphs of a detector output signal are used for a classification and discrimination of the tested objects. Four different classifiers are presented. The comparison of classification results of polyharmonic signals with the classical single tone method is also shown. Multi-frequency signals offer more detailed information, due to response function – the frequency characteristic of a detected object, than the application of standard single tone methods. Based on the measurements and analysis, a metal object can be better distinguished than when using the single tone method.

Zpracování a digitalizace analogových signálů v měřicí technice

  • Pracoviště: Katedra měření
  • Anotace:
    Kniha popisuje metody zpracování analogových signálů a jejich digitalizaci v měřicí technice. Jsou zde uvedeny obvodové prostředky analogového zpracování signálů z typických snímačů fyzikálních veličin a prostředky k jejich digitalizaci a rekonstrukci včetně popisu vybraných metod číslicového zpracování signálů, umožňujících zvýšit metrologické vlastnosti měřicího řetězce. Kniha je doplněna praktickými zásadami konstrukce analogově číslicových systémů z hlediska přenosu a izolace analogových signálů, způsobu propojování, napájení a zemnění obvodů a návrhu tištěných spojů.

A Hardware Platform for Frequency Domain Spectroscopy and Frequency Response Analysis

  • DOI: 10.12700/APH.14.8.2017.8.3
  • Odkaz: https://doi.org/10.12700/APH.14.8.2017.8.3
  • Pracoviště: Katedra měření
  • Anotace:
    This paper describes a development of a hardware platform suitable for the frequency domain spectroscopy (FDS) and frequency response analysis (FRA) applied for high-voltage machines diagnostics. The principle of the FDS and FRA methods widely used by maintenance technicians are briefly reminded. Important technical requirements for the instruments utilizing these methods are stated. A design of a hardware platform with parameters fitting both of the method and engagement of the latest electronics components is discussed. In order to verification of the design platform, a basic implementation of a vector voltmeter is described. Long term stability, phase shift sensitivity, and accuracy of the platform are evaluated.

Advanced Instrumentation for Polyharmonic Metal Detectors

  • DOI: 10.1109/TMAG.2015.2507780
  • Odkaz: https://doi.org/10.1109/TMAG.2015.2507780
  • Pracoviště: Katedra měření
  • Anotace:
    The paper describes application of polyharmonic sinc signals in devices for metal object detection. A basic problem of conventional eddy current metal detectors (induction devices in general) lies in its limited possibilities of discrimination or identification of detected objects. To better characterize the detected object, the excitation signal and the following signal processing in the detector should be done. Application of polyharmonic excitation signal and its processing could bring an opportunity to improve the determination ability. The article is focused to the polyharmonic sinc signal. Spheres of different diameters and from different ferrous and non-ferrous materials were used as specimens. Experimental measurements were processed in frequency domain - amplitude and phase spectra were calculated and presented. As part of the work, classifications of ferrous and non-ferrous materials were done based of measured data as well as classification of individual ferrous including non-ferrous materials and estimation of the size of the classified object. Support vector classifier was primarily used for data classification.

The design of an analog to digital front-end for frequency domain spectroscopy analyzer

  • DOI: 10.1109/BEC.2016.7743752
  • Odkaz: https://doi.org/10.1109/BEC.2016.7743752
  • Pracoviště: Katedra měření
  • Anotace:
    This paper describes a developing of an analog to digital front-end suitable for the frequency domain spectroscopy (FDS) of high-voltage machines. The principle of the FDS is described and the requirements for the instruments utilizing this method are stated. The design of the front-end is described as a base of an FDS analyzer instrument. A basic implementation of the vector voltmeter is described. The implementation is verified in order to stability, a phase shift sensitivity and accuracy.

CAPACITANCE AND DISSIPATION FACTOR METER FOR HIGH-VOLTAGE ELECTRICAL MACHINES

  • Pracoviště: Katedra měření
  • Anotace:
    Measurement of the capacitance and the dissipation factor of the high-voltage machines insulation systems is one of several method used in the technical diagnostics. This paper deal with the development of instrument designed for measuring capacitance and dissipation factor of such machines. There is described principle of ratio measurement method as well as developer hardware based on FPGA application. Finally the measurement error analysis is given and its correction is presented.

PARTIAL DISCHARGE DIAGNOSTIC SYSTEM FOR NON-DESTRUCTIVE TESTING OF HIGH-VOLTAGE MACHINES

  • Pracoviště: Katedra měření
  • Anotace:
    This paper deals with the complex design of the partial discharge system for high-voltage machines diagnostics. The result of the work is complete measurement system, which fulfils specified functionality. Implementation relies on the FPGA with the advantage of system-on-the-chip technology. This solution enables flexible and powerful signal processing. Measurement principles and methods together with the test results are also mentioned.

A Wideband Partial Discharge Meter using FPGA

  • DOI: 10.1109/DEMPED.2013.6645746
  • Odkaz: https://doi.org/10.1109/DEMPED.2013.6645746
  • Pracoviště: Katedra měření
  • Anotace:
    This paper describes a hardware design of a fully digital wideband PD meter based on application of FPGA as well as design of coupling device required for PD measurements. The designed coupling device has frequency bandwidth of 1 kHz - 10 MHz. The PD signal is digitalized by a fast 14-bit A/D convertor sampling at frequency of 50 MSa/s. The digital samples of PD signal are read by the FPGA, subsequently filtered by a number of digital FIR filter banks and stored in a 32 MB SDRAM memory. On request from PC software, the FPGA send samples in reduced form through Ethernet interface for the next signal processing and evaluation all important parameters of PD analysis. The paper also describes a design of smart charge calibrator especially developed for the PD meter testing and calibration.

Intelligent Measuring Diagnostic System for Estimation of Operation State of High Voltage Rotating and Non-rotating Electrical Machines

  • Pracoviště: Katedra měření
  • Anotace:
    This article focuses on the diagnostic system under development, which will enable to measure dissipation factor, energy and frequency of partial discharge occurrence. Based on measured results the related software will help to determine probable time between failures of power equipments. This procedure will result in significant economic savings in terms of inspections, repairs and shutdowns of equipments.

DAC Testing Using Impulse Signals

  • Autoři: Fexa, P., doc. Ing. Josef Vedral, CSc.,
  • Publikace: Metrology and Measurement Systems. 2012, 19(1), 105-114. ISSN 0860-8229.
  • Rok: 2012
  • DOI: 10.2478/v10178-012-0009-8
  • Odkaz: https://doi.org/10.2478/v10178-012-0009-8
  • Pracoviště: Katedra měření
  • Anotace:
    The Multi-Tone (MT) signal with uniform amplitudes can be used for DAC testing. This paper shows an easier way to generate a MT signal using several impulse signals. The article also analyzes qualities of methods for testing the dynamic parameters of Digital to Analog Converters using an impulse signal. The MT, Damped Sine Wave (DSW) and Sinx/x (SINC) signals will be used as the source for these tests. The Effective Number of Bits (ENOB) and Signal to noise and distortion (SINAD) are evaluated in the frequency domain and they are modified using the Crest Factor (CF) correction and compared with the standard results of the Sine Wave FFT test. The first advantage of the test using an impulse signal is that you need fewer input parameters to create the band signal for testing the DAC. The second one is to reduce the testing time using a band signal in comparison with multiple tests using a single sine wave.

Metal Object Detection and Discrimination Using Sinc Signal

  • Autoři: Ing. Jakub Svatoš, Ph.D., doc. Ing. Josef Vedral, CSc., Nováček, P.
  • Publikace: BEC 2012 - Proceedings of the 13th Biennial Baltic Electronics Conference. Tallinn: Tallinn Technical University, 2012. p. 307-310. ISSN 1736-3705. ISBN 978-1467-3277-4-9.
  • Rok: 2012
  • DOI: 10.1109/BEC.2012.6376878
  • Odkaz: https://doi.org/10.1109/BEC.2012.6376878
  • Pracoviště: Katedra měření
  • Anotace:
    The paper shows application of non-traditional excitation signal Sinc for metal detection and discrimination of detected objects. It also briefly describes characterization of Sinc signal. Head of the All Terrain Mine Detector is used for experiment. Various spheres from different materials and with different diameters were placed in non-magnetic platform in the open air as a test target. Signal was processed in frequency domain. Spectra graphs are presented to differentiate between the different objects. On the basis of these graphs, better identification and discrimination between these objects (i.e. Anti-Personnel mines or UXO) could be done.

sin(x)/x SIGNAL UTILIZATION IN METAL DETECTION AND DISCRIMINATION

  • Pracoviště: Katedra měření
  • Anotace:
    This paper presents usage of an unusual signal (sinc signal) for metal detection and discrimination. Even in present days, differentiate between Anti-Personnel (AP) mine or unexploded ordnance (UXO) and metal garbage is a matter of high interest for scientists. In some areas, especially with contaminated or magnetic soil, 999 form 1000 alarms are false. Decrease of these false alarms is enticing and necessary in umanitarian demining. For the experiment Schiebel All-Terrain Mine Detector with testing spheres from different materials and different sizes were used. Signal from the detector was processed in frequency domain, especially phase spectra are shown and compared.

Summary of Non-traditional Methods for Metal Detection and Discrimination

  • Autoři: Ing. Jakub Svatoš, Ph.D., Nováček, P., doc. Ing. Josef Vedral, CSc.,
  • Publikace: Eurosensors XXVI - 2012 - The 26th European Conference on Solid-State Transducers. Krakow: Wydawnictwo Politechniki Krakowskiej, 2012, pp. 298-301. ISSN 1877-7058.
  • Rok: 2012
  • DOI: 10.1016/j.proeng.2012.09.142
  • Odkaz: https://doi.org/10.1016/j.proeng.2012.09.142
  • Pracoviště: Katedra měření
  • Anotace:
    This paper describes three different possibilities how to detect and distinguish between different metal garbage and mine (especially Anti-Personnel mines - AP) or UXO unexploded ordnance). A comparison of three unconventional excitation polyharmonic signals for an eddy current metal detector is presented. These signals are linear frequency sweep sinusoidal, step sweep sinusoidal, and sinc signals. Thanks to this we obtained a frequency characteristic of a detected object over a wide range of frequencies and obtained more detailed view about object than with classical methods. Amplitude and phase spectra, polar graphs as well as real and imaginary parts ot detector signal output are presented. Based on the measurements and the analyses, the distinguishing between different objects can be done in terms of the electromagnetic properties (conductivity and permeability). Polar graphs could be used for an object’s interpretation and for the manual discrimination.

The Usage of Frequency Swept Signals for Metal Detection

  • DOI: 10.1109/TMAG.2011.2173174
  • Odkaz: https://doi.org/10.1109/TMAG.2011.2173174
  • Pracoviště: Katedra měření
  • Anotace:
    The usage of frequency swept signals for an eddy current metal detector is described in this paper. The main task for researchers is to minimize false alarms which account for up to 99.9 % of the total alarms. Better discrimination should be performed to distinguish between mine and scrap metals. Firstly, a short theoretical background is presented. Secondly, experimental data measured by the search head of the metal detector ATMID is presented. The detector was excited with frequency swept sine signals from 1 kHz to 45 kHz. Synchronous demodulation was used for signal processing. Various spheres from different materials and sizes placed in the open air were used as the test targets. A grenade, without explosives, was also presented for comparison. Amplitude and phase graphs or polar graphs are presented to differentiate between the different objects.

ADC and DAC Testing Using Impulse Signals

  • Autoři: doc. Ing. Josef Vedral, CSc., Fexa, P.
  • Publikace: International Mixed Signals, Sensors and Systems Test Workshop 2011. Santa Barbara: University of California Santa Barbara, 2011. pp. 5-8. ISBN 978-0-7695-4479-3.
  • Rok: 2011
  • Pracoviště: Katedra měření
  • Anotace:
    This paper analyses of methods for testing dynamical parameters of ADC and DAC. Resultst of the tests will compared with single tone FFT test.

DAC Testing Using Modulated Signals

  • Pracoviště: Katedra měření
  • Anotace:
    This document analyses qualities of methods for testing dynamical parameters of Digital to Analog (D/A) converters using multi frequency signal. As the source for these signals, Amplitude Modulated (AM) and Frequency Modulated (FM) signals are used. These signals are often used in radio engineering. Results of the tests (like Effective Number of Bits - ENOB, Signal to noise and distortion - SINAD) are evaluated in frequency domain and they are compared with standard results of Sin Wave FFT test methods.

Developing Automated Data Acquisition System for ADC and DAC Testing

  • Autoři: Fexa, P., doc. Ing. Josef Vedral, CSc.,
  • Publikace: Intelligent Data Acquisition and Advanced Computing Systems (IDAACS). Piscataway: IEEE, 2011, pp. 39-42. ISBN 978-1-4577-1423-8.
  • Rok: 2011
  • Pracoviště: Katedra měření
  • Anotace:
    This paper shows implementation of Data Acquisition System for Analog-to-Digital-Converters ADC and Digital-to-Analog-Converters DAC in LabView. This system was developed for purpose of evaluation of ADC's and DAC's dynamic parameters using single and multifrequency signal. Virtual Instrument was created in LabView to control data generation and acquisition. Paper briefly shows you methods, which were used for ADC and DAC testing.

Metal Detector Excited by Frequency Swept

  • Pracoviště: Katedra měření
  • Anotace:
    This paper describes theoretical background of electromagnetic induction from metal objects modeling. Response function of specific case of the object`s shape - the homogenous sphere for ferromagnetic and non-ferromagnetic material is introduced. Experimental data measured by metal detector excited with Polyharmonic signal are presented. These results should lead to better identification of the buried object. As a testing target various spheres from different materials and sizes were used.

Using of Pulse Signal Sinx/x for DAC Testing

  • Autoři: doc. Ing. Josef Vedral, CSc., Fexa, P.
  • Publikace: IMEKO TC4 International Workshop on ADC Modelling, Testing and Data Converter Analysis and Design. Perugia: Universita degli Studi di Perugia, 2011. pp. 217-220. ISBN 978-1-61839-279-4.
  • Rok: 2011
  • Pracoviště: Katedra měření
  • Anotace:
    In this paper the qualities of short methods for testing dynamical parameters internal ADCs and DACs with impulses Multi-Tone and Sinx/x signal are analyzed. Practically examples are compared with standard Single-Tone Fourier Transform Test Method. This methods finds an application in the industry in less demanding economical short testing.

Using of Pulse Signals for DAC Testing

  • Autoři: Fexa, P., doc. Ing. Josef Vedral, CSc.,
  • Publikace: Applied Electronics 2011. Plzeň: University of West Bohemia, 2011, pp. 115-118. ISSN 1803-7232. ISBN 978-80-7043-987-6.
  • Rok: 2011
  • Pracoviště: Katedra měření
  • Anotace:
    The qualities of the method for testing dynamic parameters of DACs using pulse signal sinx/x are analyzed in this paper. Practical examples are compared with standard Single and Multi-Tone Digital Fourier Transform Test Methods.

ADC Testing with Poly-harmonic Signals

  • Autoři: doc. Ing. Josef Vedral, CSc.,
  • Publikace: IMS3TW - the 2010 IEEE 16th International Mixed-Signals, Sensors and Systems Test Workshop. Montpellier: Université Montpellier II, 2010, pp. 22-25. IEEE Catalog Number: CFP10MST-USB. ISBN 978-1-4244-7793-7. Available from: http://www.lirmm.fr/~w3mic/IMS3TW10/
  • Rok: 2010
  • Pracoviště: Katedra měření
  • Anotace:
    In this paper the qualities of methods for testing dynamical parameters of A/D converters with discrete polyharmonic signals are analyzed. Results of test with Multi-Tone signal with equivalent amplitudes, AM and FM signals are compared with standard Single-Tone Fourier Transform Test.

Comparative Testing of Dynamic Parameters DACs with Multi-Tone Signals (ID 75)

  • Pracoviště: Katedra měření
  • Anotace:
    In this paper there are presented methods for testing dynamic parameters DA converters with multi-tone signals. Results of this test with discrete multi-tone signals and equivalent amplitudes, AM and FM signals compared with standard test with Single-Tone Fourier Test.

FM and QAM Signals for ADC Testing

  • Pracoviště: Katedra měření
  • Anotace:
    In this paper the qualities of methods for testing dynamical parameters of A/D converters with analog frequency modulated and quadrature modulated signals are analyzed. Results of test are compared with standard Single-Tone Fourier Transform Test.

Metal Detector Excited by Polyharmonic Signals

  • Pracoviště: Katedra měření
  • Anotace:
    In this paper theoretical background of electromagnetic induction modeling is presented. Response function of specific case of the shape - homogenous sphere for ferromagnetic and non-ferromagnetic is introduced. Some experimental data measured on metal detector excited by Polyharmonic signal are also presented.

Signal Processing in Partial Discharge Measurement

  • Autoři: doc. Ing. Josef Vedral, CSc., Kříž, M.
  • Publikace: Metrology and Measurement Systems. 2010, XVII(1), 55-63. ISSN 0860-8229.
  • Rok: 2010
  • Pracoviště: Katedra měření
  • Anotace:
    The paper presents traditional analogue and new digital techniques in partial discharge measurement. The discharge current pulses are measured from high voltage machines like power plant generators and transformers. The presented modern digital techniques are suitable for all measurements where impulse energy will be calculated.

Using of AM and FM Signal for ADC Testing

  • Autoři: doc. Ing. Josef Vedral, CSc., Fexa, P., Ing. Jakub Svatoš, Ph.D.,
  • Publikace: I2MTC International Instrumentation and Measurement Technology Conference. Piscataway: IEEE, 2010, pp. 508-511. ISSN 1091-5281. ISBN 978-1-4244-2833-5. Available from: http://ieee-ims.org/conferences/imtc/2010/
  • Rok: 2010
  • DOI: 10.1109/IMTC.2010.5488235
  • Odkaz: https://doi.org/10.1109/IMTC.2010.5488235
  • Pracoviště: Katedra měření
  • Anotace:
    In this paper qualities of methods for testing dynamical parameters of A/D converters with poly-harmonics signals are analyzed. As source for these signals amplitude and frequency modulation signals are used. These signals are often used in radio engineering. Results of test in time and frequency domain (Effective Number of Bits, Total Harmonic Distortion, Signal Non-harmonic Distortion, Spurious Free Dynamic Range, and Intermodulation Distortion) are compared with standard results of Sin Wave Fit and FFT test methods.

Digital Signal Chains in Partial Discharge Measurement

  • Autoři: doc. Ing. Josef Vedral, CSc., Kříž, M.
  • Publikace: IDAACS 2009 - IEEE International Workshop on Intelligent Data Acquisition and Advanced Computing Systems: Technology and Applications. Como: IEEE Instrumentation and Measurement Society, 2009, pp. 82-86. ISBN 978-1-4244-4881-4.
  • Rok: 2009
  • Pracoviště: Katedra měření
  • Anotace:
    The paper presents traditional analogue and digital signal processing in partial discharge measurement. The discharge current pulses are measured from high voltage machines. The presented modern digital techniques for current impulse energy measurement.

Dynamic Testing of Audio Codec

  • Pracoviště: Katedra měření
  • Anotace:
    This paper is to show the methods of dynamic parameters testing of high quality audio codec with 24 bits nominal resolution. In the paper are briefly the best Sine Wave Fit Test, Spectral Purity Test and Noise Histogram Test presented. The above mentioned testing methods are then used for testing of these ADCs and obtained data are discussed.

Economical Test of Internal ADC in Embedded Systems

  • Autoři: doc. Ing. Josef Vedral, CSc., Ing. Jakub Svatoš, Ph.D., Fexa, P.
  • Publikace: XIX IMEKO World Congress 2009 - Fundamental and Applied Metrology. Lisbon: Instituto Superior Técnico/Instituto de Telecomunicaçoes Portugal, 2009, pp. 702-705. ISBN 978-963-88410-0-1.
  • Rok: 2009
  • Pracoviště: Katedra měření
  • Anotace:
    This paper describes two methods for economical test of dynamic parameters ADCs in embedded Data Acquisition Systems. First method is Exponential Fit Test, second method is Wobbler Test. Common testing methods are mentioned as far the accuracy and time necessary for the complete test are concerned. The tests for fast evaluation of the dependence of an effective number of bits on frequency of input signal are described and the comparison of proposed method with the standard methods is given.

High Resolution Audio Codec Test

  • Autoři: Fexa, P., Ing. Jakub Svatoš, Ph.D., doc. Ing. Josef Vedral, CSc.,
  • Publikace: MEASUREMENT 2009 - Proceedings of the 7th International Conference on Measurement. Bratislava: Institute of Measurement Science, 2009. pp. 206-209. ISBN 978-80-969672-1-6.
  • Rok: 2009
  • Pracoviště: Katedra měření
  • Anotace:
    In this paper is presented the Sine Wave Fit Test, Spectral Purity Test and Noise Histogram Test methods for testing of dynamic parameters audio codec with 24 bits nominal resolution. In frequency range 20 Hz to 20 kHz was determine Effective Number of Bits 14,4, Signal Noise and Distortion 89 dB and Total Harmonic Distortion 110 dB.

Laboratory of Analog Signal Processing and Digitizing at FEE CTU in Prague

  • Autoři: doc. Ing. Josef Vedral, CSc., Ing. Jakub Svatoš, Ph.D., Fexa, P.
  • Publikace: XIX IMEKO World Congress 2009 - Fundamental and Applied Metrology. Lisbon: Instituto Superior Técnico/Instituto de Telecomunicaçoes Portugal, 2009. pp. 15-19. ISBN 978-963-88410-0-1.
  • Rok: 2009
  • Pracoviště: Katedra měření
  • Anotace:
    In the paper are stated methods of education of electronic measurement circuits at Department of Measurement of FEE CTU in Prague. There are specified typically themes applied in bachelor and master grade of study. The education is supported by the set of electronic function units, universal laboratory units LABORO and simulation program MULTISIM.

Methods for Economical Test of Dynamic Parameters ADCs

  • Pracoviště: Katedra měření
  • Anotace:
    This paper describes two methods for economical test of dynamic parameters ADCs. First method is Exponential Fit Test, second method is Wobbler Test. Common testing methods are mentioned as far the accuracy and time necessary for the complete test are concerned. The tests for fast evaluation of the dependence of an effective number of bits on frequency of input signal are described and the comparison of proposed method with the standard methods is given. The suitable area of proposed method application is "each-piece" factory testing requiring extremely short time testing.

Methods of Education Electronic Measurement Circuits and Systems at FEE CTU

  • Pracoviště: Katedra měření
  • Anotace:
    In the paper are stated methods of education electronic measurement circuits at Department of Measurement of FEE CTU in Prague. There are specified typically themes applied in bachelor and master grade of study. The education is supported by the set of electronic function units, universal laboratory units LABORO and simulation program MULTISIM.

Exponential Fit Test - Theoretical Analysis and Practically Implementation

  • Autoři: doc. Ing. Josef Vedral, CSc.,
  • Publikace: 13th Workshop on ADC Modelling and Testing. University of Florence, 2008. pp. 1033-1036. ISBN 978-88-903149-3-3.
  • Rok: 2008
  • Pracoviště: Katedra měření
  • Anotace:
    ADC testing by means of exponential signal is presented in the article. Time and frequency analysis of the signal is performed and Signal-to-Noise Ratio and Effective Number of Bits is calculated by means of Best-Exponential Fit Test. The approach has been verified on 24-bit Flexible Resolution Digitizer PXI-5922 by National Instruments. Results comparable with classical sine-fit method indicate the possibility of consideration of the proposed method as an alternative digitizer test method.

Implementation of ADC Wobbler Test in FPGA

  • Autoři: doc. Ing. Josef Vedral, CSc.,
  • Publikace: DCIS 2008 - Conference on Design of Circuits and Integrated Systems. Grenoble: TIMA, 2008. ISBN 978-2-84813-124-5.
  • Rok: 2008
  • Pracoviště: Katedra měření
  • Anotace:
    A short sine wave fit test method for embedded ADC systems is investigated. Common testing methods are mentioned as far as the accuracy and time necessary for the complete test are concerned. A wobbler test for fast evaluation of the dependence of an effective number of bits on frequency of input signal is described and the comparison of proposed method with the standard methods is given. The suitable area of proposed method application is "each-piece" factory testing requiring extremely short testing time.

Aspects of ADC Verification

  • Autoři: doc. Ing. Josef Vedral, CSc.,
  • Publikace: Testmethoden und Zuverlässigkeit von Schaltungen und Systemen. Erlangen: Universität Erlangen-Nürnberg, 2007. pp. 23-25.
  • Rok: 2007
  • Pracoviště: Katedra měření
  • Anotace:
    The object of this paper is to show the methods of testing of audio converters with 24 bits nominal resolution. In the paper are briefly presented the best sinusoidal curve fit test method and spectral purity test. The above mentioned testing methods are then used for testing of these ADCs and obtained data are discussed.

Pseudorandom Noise Generator for ADC Testing

  • Autoři: doc. Ing. Josef Vedral, CSc., Neškudla, J.
  • Publikace: 12th TC4 International Workshop on ADC Modelling and Testing. Iasi: CERMI Publishing House, 2007. pp. 47-50. ISBN 978-973-667-264-4.
  • Rok: 2007
  • Pracoviště: Katedra měření
  • Anotace:
    This paper demonstrates method of noise signal generation for ADC testing. Digital pseudo-random number generator based on LFSR. The signal should be used to measure parameters of AD converters.

White Noise Signal Generator for ADC Testing

  • Autoři: doc. Ing. Josef Vedral, CSc., Neškudla, J.
  • Publikace: IMSTW, GTW 07 - 13th International Mixed Signals Testing Workshop and 3rd International GHz/Gbps Test Workshop. Póvoa de Varzim: IEEE Computer Society, TTTC, 2007. pp. 153-157. ISBN 978-972-99181-2-4.
  • Rok: 2007
  • Pracoviště: Katedra měření
  • Anotace:
    This paper demonstrates methods of noise signal generation for ADC testing with pseudo-random number generatoration. The objective of this exploration is to develop device for generation noise signal with uniformly distributed amplitudes. The signal should be used to measure parameters of AD converters.

Digitally Controlled White Noise Generator

  • Autoři: Neškudla, J., doc. Ing. Josef Vedral, CSc.,
  • Publikace: IMEKO - XVIII World Congress and IV Brazilian Congress of Metrology. Rio de Janeiro: IMEKO, 2006.
  • Rok: 2006
  • Pracoviště: Katedra měření
  • Anotace:
    This paper demonstrates a new method of digital generation of white noise signal with given statistical distribution. Digital pseudo-random number generator based on LFSR and a single-bit Digital/Analogue converter are used. The objective of this exploration is a testing device usable to measure parameters of Analogue/Digital converters using Step-Gauss test method. Also new theoretically possible way of generating uniformly distributed noise signal is shown.

Novel Digital White Noise Source

  • Autoři: Neškudla, J., doc. Ing. Josef Vedral, CSc.,
  • Publikace: Electronic Devices and Systems - IMAPS CS International Conference 2006. Brno: Vysoké učení technické v Brně, 2006. pp. 101-106. ISBN 80-214-3246-2.
  • Rok: 2006
  • Pracoviště: Katedra měření
  • Anotace:
    A new method of white noise digital generation with pseudorandom number generator with linear feedback shift register is demonstrated in this paper.

Quality Testing of 24 Bit Audio Codecs

  • Autoři: doc. Ing. Josef Vedral, CSc., Neškudla, J.
  • Publikace: Electronic Devices and Systems - IMAPS CS International Conference 2006. Brno: Vysoké učení technické v Brně, 2006. pp. 125-130. ISBN 80-214-3246-2.
  • Rok: 2006
  • Pracoviště: Katedra měření
  • Anotace:
    The object of this paper is to show the methods of testing of audio codec chip STAC 9460S with 24 bits nominal resolution. In the paper are presented the best sinusoidal curve fit test methods and spectral purity test. The above mentioned testing methods are then used for testing of these ADCs and obtained data are discussed.

Measurements of ADCs Effective Resolution

  • Autoři: prof. Ing. Jan Holub, Ph.D., Neškudla, J., doc. Ing. Josef Vedral, CSc.,
  • Publikace: ADDA 2005 - The 5th IEE International Conference on Advanced A/D and D/A Conversion Techniques and their Applications. Limerick: The IEE Measurement, Sensors, Instrumentation and NDT Professional Network, 2005. p. 255-257. ISBN 0-86341-542-3.
  • Rok: 2005
  • Pracoviště: Katedra měření
  • Anotace:
    The article describes some aspects of understanding, defining and measurements of high effective resolution of ADC in Microconvertor ADUC834. The disadvantages and misleading results of commonly used definition are shown and possible solutions are discussed. Finally, one new solution is given and arguments for its correctness and usability are collected.

Testing of ADCS with Noise Signal

  • Pracoviště: Katedra měření
  • Anotace:
    High-linearity and high-resolution AD converters that are difficult to test by standard methods using deterministic signal [1] can be tested by means of stochastic test methods. Histogram test can use various input signals and principally allows use noise as the input signal. To overcome difficulties related to generation of large-scale uniformly distributed stochastic signal, a method based on superposition of Gaussian noises with equidistantly spaced DC shifts has been proposed and theoretical analysis has been provided in [2]. In current development stage, it can host the following 16-bits ADCs with SAR transfer technology.

Dynamic Parameters Testing of 24-bit Resolution ADCs

High Resolution ADC Data Acquisition System

Measurements of Effective Resolution of ADC in Microconverter ADUC834

  • Autoři: doc. Ing. Josef Vedral, CSc., prof. Ing. Jan Holub, Ph.D.,
  • Publikace: DDECS - Proceedings of 7th IEEE Design and Diagnostics of Electronic Circuits and Systems Workshop. Stará Lesná: Institute of Informatics, Slovak Akademy of Sciences, Bratislava, 2004. pp. 255-258. ISBN 80-969117-9-1.
  • Rok: 2004

Step Gauss Test - New Method for Testing of ADCs

Stochastic Test of 24 bit-AD Converter - Case Study

Stochastic Test of 24 bit-AD Converter - Case Study

Stochastic Testing of ADC - Step-Gauss Method

Application of Noise Signal for Testing High Resolution ADCs

Dynamic Testing of 16 bit ADC with Sinewave and Stochastic Signals

Methods of Partial Discharges Measurement

  • Autoři: Kříž, M., doc. Ing. Josef Vedral, CSc.,
  • Publikace: Proceedings of Workshop 2003. Praha: České vysoké učení technické v Praze, 2003, pp. 464-465. ISBN 80-01-02708-2.
  • Rok: 2003

Quantification of Partial Discharges Charge

  • Autoři: Kříž, M., doc. Ing. Josef Vedral, CSc.,
  • Publikace: Measurement 2003 - Proceedings of the 4th International Conference on Measurement. Bratislava: Slovak Academy of Sciences, Institute of Measurement Science, 2003. pp. 407-410. ISBN 80-967402-6-1.
  • Rok: 2003

Step-Gauss Stochastic Testing Method Application for Transportable Reference ADC Device

Stochastic Test Method Application for 16-Bit Reference ADC Device

  • Autoři: prof. Ing. Jan Holub, Ph.D., Komárek, M., Kříž, M., doc. Ing. Josef Vedral, CSc.,
  • Publikace: Measurement 2003 - Proceedings of the 4th International Conference on Measurement. Bratislava: Slovak Academy of Sciences, Institute of Measurement Science, 2003. pp. 95-98. ISBN 80-967402-6-1.
  • Rok: 2003

Stochastic Test Method Application for 16-Bit Reference ADC Device

Testing of High Resolution ADCs with Deterministic and Stochastic Signals

Transportable Reference AD Device - New Innovated Version

Transportable Reference AD Device - New Innovated Version

Aspects of ADC Effective Resolution: Definitions and Measurements

Aspects of ADC Effective Resolution: Definitions and Measurements

High Resolution ADC Testing by Means of Standard Test Methods

Histogram Test of Sigma Delta ADC

Improvement of Stepp-Gauss ADC Stochastic Test Method

Improvement of Stepp-Gauss ADC Stochastic Test Method

Methods for Testing of High Resolution ADC

Reference ADC Standard - Comparison of ADC Testing Methods

Stochastic Testing Signals in ADC Testing

Testing of High Resolution AD Converters

  • Autoři: Andrle, M., doc. Ing. Josef Vedral, CSc.,
  • Publikace: Proceedings of Workshop 2002. Praha: České vysoké učení technické v Praze, 2002. pp. 438-439. ISBN 80-01-02511-X.
  • Rok: 2002

Testing of Static and Dynamic Parameters of Digital Oscilloscopes

  • Autoři: Al-Iriany, A., Andrle, M., doc. Ing. Josef Vedral, CSc.,
  • Publikace: Applied Electronics 2002. Plzeň: ZČU Plzeň, 2002, pp. 15-18. ISBN 80-7082-881-1.
  • Rok: 2002

Time versus Frequency-Domain Methods for High Resolution ADC Testing

Transportable High Stable Reference AD Module

ADC Testing by Means of Stochastical Signal

Combined Testing Signal for ADC Histogram Test

Digital Oscilloscopes Testing System

Electronic Measuring Circuits Laboratory Exercises at Dept. of Measurement of FEE CTU

Evaluation of Frequency Dependence of Effective Number of Bits by means of Stochastic Testing Signal

Evaluation of Frequency Dependence of Effective Number of Bits by means of Stochastic Testing Signal

How to Exercise Complex Measurements

How to Exercise Complex Measurements

Measuring System for Testing of Digital Oscilloscopes

Metrological Aspects of Digital Oscilloscopes

Oscilloscope Testing by Means of Stochastic Signal

Stochastic Testing of A/D Converters-Step-Gauss Method

Transfer Standard ADC

Transportable AD Box for Comparative Measurement

Transportable AD Box for Comparative Measurement

Transportable Reference AD Converter

ADC Testing Using Combined Test Signal

Measuring of Effective Resolution of Sigma-Delta ADC

Measuring of Effective Resolution of Sum-Delta ADC

Practical Experience with Linearity Improvement in Dithered ADC

Signal Source for Statistical Testing of ADC

Statistical Method for Testing of Sigma-Delta Converters

Statistical Testing of Sigma Delta ADCs

Stochastic Testing of Analog-to-Digital-Converters

Stochastic Testing Signals in ADC Testing

Testing of Digital Oscilloscopes

Transportable High Stable Reference AD Module

Vlastnosti analogových vstupů mikropočítače 80552

A New Time-Saving Method for ADC Testing

A Quadrature Bridge for QHE-Based Calibration of Capacitance Standards

Chirp Based Method for ADC Testing: Simulation and Evaluation

High-Resolution Multiplexing Analog-to-Digital Module

  • Autoři: prof. Ing. Jan Holub, Ph.D., doc. Ing. Josef Vedral, CSc.,
  • Publikace: 8th Scientific Conference Theoretical Electrical Engineering and Electrical Measurement. Košice: Dep. of Theoretical Electrical Engineering and El. Measurement FEI TU of Košice, 1999. pp. 109-116.
  • Rok: 1999

Statistical Method for Testing of Sigma-Delta Converters

Testing of High-Resolution Multiplexing A/D Converters

Číslicové měření parametrů neharmonických signálů

  • Autoři: doc. Ing. Josef Vedral, CSc.,
  • Publikace: Konferencia Elektrotechnika a energetika 98. Bratislava: STU v Bratislave, FEI, 1998. pp. 11-13. ISSN 1335-2547.
  • Rok: 1998

Full-Test of Performance of ADC Input in Single-Chip Microcontrollers

Testing of Dynamic Performance of ADC Input in Single-Chip Microcontrollers

DC Testing of ADC Input in Single-Chip Microcontrollers

  • Autoři: Krecl, J., doc. Ing. Josef Vedral, CSc.,
  • Publikace: XIV IMEKO World Congress: New Measurements - Challenges and Visions. Helsinki: Finnish Society of Automation, 1997. pp. 86-90. ISBN 951-96567-7-4.
  • Rok: 1997

Dithered Quantizer of ADC Plug-In Card: Theoretical Model and Practical Testing

Měřicí systém s korekcí nelinearit a adaptivní rozlišitelností na bázi zásuvné měřicí karty do PC

Metody testování A/D převodníků

  • Autoři: doc. Ing. Josef Vedral, CSc.,
  • Publikace: A-Č a Č-A převodníky - typy a aplikace. Ostrava: Přírodovědecká fakulta OU, 1997, pp. 47-61.
  • Rok: 1997

Návrh integrovaných analogových filtrů počítačem

Parametry A/D převodníků a metody jejich testování

Vlastnosti analogových vstupů a výstupů mikroprocesoru 80552

  • Autoři: Krecl, J., doc. Ing. Josef Vedral, CSc.,
  • Publikace: Journal of Electrical Engineering. 1997, 48(10), 118-120. ISSN 0013-578X.
  • Rok: 1997

Využití spínaných filtrů v měřicí technice

Zvýšení rozlišovací schopnosti AD převodníku pomocí ditheringu

Measuring of Flash A/D Converters in Real Time

  • Autoři: doc. Ing. Josef Vedral, CSc., Krecl, J.
  • Publikace: International Workshop on ADC Modelling. Salerno: CUES, 1996, pp. 78-83.
  • Rok: 1996
  • Pracoviště: Katedra měření
  • Anotace:
    Měření A/D převodníků metodami nejlépe proložené sinusovky, spektrální analýzy a histogramové metody

Metody zpracování signálu z PSD snímače

  • Autoři: Krecl, J., doc. Ing. Josef Vedral, CSc.,
  • Publikace: Snímače - Senzory - Aplikace. Ostrava: Dům techniky, 1996, pp. 19-28.
  • Rok: 1996
  • Pracoviště: Katedra měření
  • Anotace:
    Spojité jednodimenzionální PSD snímače optického záření a metody zpracování jejich signálů

Testing Flash A/D Converters in Real Time

  • Autoři: doc. Ing. Josef Vedral, CSc., Krecl, J.
  • Publikace: Proceedings of Baltic Electronic Conference BEC 96. Tallinn: Tallinn Technical University, 1996, pp. 67-70. ISBN 9985-59-026-0.
  • Rok: 1996
  • Pracoviště: Katedra měření
  • Anotace:
    Metody pro dynamické testování AD převodníků

Zápisník přechodových dějů

  • Pracoviště: Katedra měření
  • Anotace:
    Zápisník přechodových dějů s jednočipovým mikroprocesorem

Dynamic Testing of A/D Plug-in Boards

Signal Processing for Flash AD Converters

  • Autoři: doc. Ing. Josef Vedral, CSc., Krecl, J.
  • Publikace: 7th International Symposium on Modern Electrical and Magnetic Measurement. Part 1. Praha: ČVUT FEL, Elektra, 1995, pp. 502-506. ISBN 80-01-01360-X.
  • Rok: 1995

System for the Measurement of the Bore Temperature Profile

  • Autoři: Satorie, M., doc. Ing. Josef Vedral, CSc.,
  • Publikace: Workshop 95. Praha: České vysoké učení technické v Praze, 1995, pp. 655-656.
  • Rok: 1995

Thermal Probe for Measurement the Bore Temperature Profile

Dynamic Testing of A/D Converters

  • Autoři: doc. Ing. Josef Vedral, CSc.,
  • Publikace: From Measurement to Innovation. Proc. of the XIII IMEKO World Congress. Torino: IMEKO, 1994, pp. 415-420.
  • Rok: 1994

Measuring of A/D Converters with Harmonic Signal

Měření dynamických vlastností rychlých A/Č převodníků

An On-Line Signal Averager

  • Autoři: Kříž, F., doc. Ing. Josef Vedral, CSc.,
  • Publikace: Workshop 93. Praha: České vysoké učení technické v Praze, 1993. pp. 145-146.
  • Rok: 1993

Signals with Noise Components Processing on the Averaging Principle

  • Autoři: doc. Ing. Josef Vedral, CSc., Kříž, F.
  • Publikace: Intelligent Instrumentation for Remote and On-Site Measurements. Brussels: IMEKO, 1993. pp. 71-76. ISBN 90-9006205-X.
  • Rok: 1993

Za stránku zodpovídá: Ing. Mgr. Radovan Suk