Lidé

Ing. Jakub Svatoš, Ph.D.

Všechny publikace

Cepstral Coefficients Effectiveness for Gunshot Classifying

  • DOI: 10.1088/1361-6501/ad3c5d
  • Odkaz: https://doi.org/10.1088/1361-6501/ad3c5d
  • Pracoviště: Katedra měření
  • Anotace:
    This paper analyses the efficiency of various frequency cepstral coefficients (fCC) in a non-speech application, specifically in classifying acoustic impulse events - gunshots. There are various methods for such event identification available. The majority of these methods are based on time or frequency domain algorithms. However, both of these domains have their limitations and disadvantages. In this article, an fCC, combining the advantages of both frequency and time domains, is presented and analyzed. These originally speech features showed potential not only in speech-related applications but also in other acoustic applications. The comparison of the classification efficiency based on features obtained using four different fCC, namely Mel-frequency Cepstral Coefficients (MFCC), Inverse Mel-frequency Cepstral Coefficients (IMFCC), Linear-frequency Cepstral Coefficients (LFCC), and Gammatone-frequency Cepstral Coefficients (GTCC) is presented. An optimal frame length for an fCC calculation is also explored. Various gunshots from short guns and rifle guns of different calibers and multiple acoustic impulse events, similar to the gunshots, to represent false alarms are used. More than six hundred acoustic events records have been acquired and used for training and validation of two designed classifiers, Support Vector Machine, and Neural Network. Accuracy, Recall and Matthew's correlation coefficient measure the classification success rate. The results reveal the superiority of GFCC to other analyzed methods.

Design and Modeling of An Axisymmetric Eddy Current Sensor for Speed Measurement of Nonmagnetic Rods

  • DOI: 10.1016/j.sna.2022.113728
  • Odkaz: https://doi.org/10.1016/j.sna.2022.113728
  • Pracoviště: Katedra elektromagnetického pole, Katedra měření
  • Anotace:
    This paper presents the design and modeling of an eddy current speed sensor for nonmagnetic moving rods with an axisymmetric configuration. The sensor consists of two antiserially connected excitation coils and one pick up coil located between two excitation coils. A novel computational approach using the combined finite difference method and Fourier series is proposed for the modeling and simulations of the eddy current speed sensor. The effects of the outer diameters of moving nonmagnetic rods and their electrical conductivities on the performance of speed sensor are originally evaluated. The results of the modeling for the eddy current speed sensor are compared with the measurements at time varying speeds and various frequencies. The comparison between modeling and experimental results shows the appropriateness of the eddy current speed sensor for the speed measurement of nonmagnetic rods.

How the COVID-19 Changed the Hands-on Laboratory Classes of Electrical Measurement

  • DOI: 10.21014/actaimeko.v11i4.1301
  • Odkaz: https://doi.org/10.21014/actaimeko.v11i4.1301
  • Pracoviště: Katedra měření
  • Anotace:
    This article depicts how COVID-19 affected practical teaching at Czech Technical University in Prague, Faculty of Electrical Engineering, Department of Measurement. It introduces the subject of Electrical Measurement and its hands-on laboratory classes. The course applies to more than 100 undergraduate students per semester. Since COVID-19 mainly affected the teaching of the hands-on laboratory courses, the article narrates how the COVID-19 lockdown has changed classes. An experience with the rapid transformation of lectures during the lockdown focusing on the hands-on laboratory classes is discussed, and the improvements that have been done to preserve its objectives, but also to adapt them to another possible lockdown, and the need to switch to the distance teaching, is revealed. The changes have been inspired by the results of a survey carried out among more than 250 students. The outline of the laboratory tasks transformation with an emphasis on the possibility of switching the real face-to-face measurement to the distance teaching remote lectures is described. The change includes reducing the number of laboratory tasks taught while preserving most of the objectives. All 11 new laboratory tasks are described in detail, and it is discussed how the possible change from hands-on to remote classes will affect every task.

Increasing of Sampling Rate of Internal ADC in Microcontrollers by Equivalent-Time Sampling

  • Pracoviště: Katedra měření
  • Anotace:
    The paper describes the Equivalent-Time Sampling (ETS) in Software-Defined Instruments (SDI) - typically oscilloscopes. It introduces a possible solution of the microcontrollers drawback caused by the maximal sampling frequency and its limitations in digitizing quick transient responses. The principle of ETS used in microcontrollers is explained, and the jitter effect is taken into account. Analog-to-digital converter input model and real properties of software-defined oscilloscope from ETS point of view are introduced and explained. In the system for circuit behavior analysis as a step response, where a microcontroller with internal peripherals (pulse-width modulation and analog-to-digital converter) is used for a test signal generation and data digitization, the use of ETS may increase the equivalent sampling rate of the internal analog-to-digital converter up to tens of MSa/s.

Online Teaching of Practical Classes Under the Covid-19 Restrictions

  • DOI: 10.1016/j.measen.2022.100378
  • Odkaz: https://doi.org/10.1016/j.measen.2022.100378
  • Pracoviště: Katedra měření
  • Anotace:
    COVID -19 pandemic and its restrictions bring new challenges to all aspects and phases of higher education. At universities, new remote formats have been developed and deployed for lectures and laboratory exercises. This article addresses challenges and introduces the new experience with lectures and laboratory classes during the pandemic time at the Department of Measurement of the Czech Technical University in Prague, Faculty of Electrical Engineering. Based on the student survey of more than 250 students describes the possibilities of how to adapt the lectures during the lockdown. The article also introduces the Home Lab, a tool developed in the department that helps in distance teaching practical electronic classes. Home Lab includes two parts with functional groups, a Laboratory Experimental Device and a System of Measurement Instruments. The article also shows the opportunity for suitable remote exercises and variants of circuits that can be easily assembled and measured using Software Defined Instrument based on various microcontrollers. A detailed description of all Software Defined Instruments is also present. During the Pandemic, the home lab model was successfully practically verified during distance learning in three subjects, with more than 150 students per semester. It has also been shown that the Home Lab can be successfully deployed for a semester project. The article also presents experience with the teaching software-oriented courses. At the end of the article, practical knowledge and an experience from distance teaching during a three-semester lockdown are shared.

Thickness Evaluation of Hollow Nonmagnetic Cylinders Utilizing a Motional Eddy Current

  • DOI: 10.1016/j.measurement.2021.110463
  • Odkaz: https://doi.org/10.1016/j.measurement.2021.110463
  • Pracoviště: Katedra elektromagnetického pole, Katedra měření
  • Anotace:
    This paper presents a way to calculate the shell thickness of nonmagnetic hollow cylinders for nondestructive applications. Aluminum cylinders with a solid structure and with a hollow structure are considered. The motion component of the induced eddy currents in a conductive cylinder is utilized to evaluate the shell thickness of hollow conductive cylinders at various frequencies and at variable speeds. One axisymmetric excitation coil and two axisymmetric pickup coils with antiserial connection are used. An analytical method using an axisymmetric computational model is developed for a parametric analysis of solid and hollow cylinder structures and shell thickness calculations, in which Fourier series are utilized. A 2D axisymmetric finite element method is also performed for a comparison with the results of the analytical method. The measurements at variable speeds and at various frequencies are presented with various hollow aluminum cylinders. The high linearity of the induced voltage versus the speed curve makes it possible to calculate the shell thickness of nonmagnetic hollow cylinders at different speeds.

Metody Výuky Praktických Předmětů na Katedře Měření FEL ČVUT v Době Covidu

  • Pracoviště: Katedra měření
  • Anotace:
    Pandemie COVID-19 prakticky přes noc dramaticky změnila nebo dokonce dočasně zastavila výuku na mnoha univerzitách. Tato situace byla výzvou zejména pro technické univerzity s původně spoustou praktických činností a laboratorních cvičení, protože vyžadovala vytvoření stabilního a plnohodnotného online vzdělávacího systému. Vše, co dosud probíhalo formou přímého kontaktu, od samotných přednášek, seminářů, praktických ukázek a laboratorních cvičení, přes písemné testy až po ústní zkoušky, bylo nutné převést do digitální podoby, o dalších právních a administrativních procesech pro zajištění výuky nemluvě. Významnou výhodou FEL ČVUT bylo, že drtivá většina pedagogů již měla předchozí zkušenosti s poskytováním online vzdělávání a disponovala řadou nástrojů, které bylo možné k tomuto účelu použít. Rychlý přechod z prezenční formy studia na distanční nicméně vyžadoval přehodnocení koncepce organizace výuky a zajištění řady souvisejících činností, zejména v oblasti komunikace, plánování vzdělávacích aktivit a výběru vhodných metod.

Online teaching at CTU in Prague aka university under COVID restrictions

  • DOI: 10.1016/j.measen.2021.100121
  • Odkaz: https://doi.org/10.1016/j.measen.2021.100121
  • Pracoviště: Katedra měření
  • Anotace:
    Covid-19 related restrictions bring new challenges to all aspects and phases of higher education. At universities, new remote formats are deployed or even developed both for lectures and laboratory exercises. This article addresses new challenges and describes the experience with lessons during the pandemic time at the Department of Measurement of the Czech Technical University in Prague, Faculty of Electrical Engineering. It introduces the best practices exercised using the Home Lab, which helps in distance teaching of practical electronic classes. Home Lab includes two models with functional groups, a Laboratory Experimental Device and System of Measurement Instruments. The article also shows the possibilities of suitable remote exercises and variants of circuits that can be easily assembled and measured using Software Defined Instrument based on STM microcontrollers. During the pandemic, the home lab model was successfully practically verified during distance learning in three classes, with more than 150 students. The article also presents experience with the teaching of software-oriented courses. At first glance, their transformation can be viewed as straightforward. However, practical realization reveals few remarkable details.

System for an Acoustic Detection, Localization and Classification

  • DOI: 10.21014/acta_imeko.v10i2.1041
  • Odkaz: https://doi.org/10.21014/acta_imeko.v10i2.1041
  • Pracoviště: Katedra měření
  • Anotace:
    At present, acoustic detection techniques of gunshots (gunshot detection and its classification) are increasingly being used not only for military applications but also for civilian purposes. Detection, localization, and classification of a dangerous event such as gunshots employing acoustic detection is a perspective alternative to visual detection, which is commonly used. In certain situations, to detect and localize a source of a gunshot, an automatic acoustic detection system, which can classify the caliber, may be preferable. This paper presents a system for acoustic detection, which can detect, localize and classify acoustic events such as gunshots. The system has been tested in open and closed shooting ranges and tested firearms are 9 mm short gun, 6.35 mm short gun, .22 short gun, and .22 rifle gun with various subsonic and supersonic ammunition. As “false alarms,” sets of different impulse acoustic events like door slams, breaking glass, etc. have been used. Localization and classification algorithms are also introduced. To successfully classify the tested acoustic signals, Continuous Wavelet and Mel Frequency Transformation methods have been used for the signal processing, and the fully two-layer connected neural network has been implemented. The results show that the acoustic detector can be used for reliable gunshot detection, localization, and classification.

A measurement system for the long-term diagnostics of the thermal and technical properties of wooden houses

  • DOI: 10.21014/ACTA_IMEKO.V9I3.762
  • Odkaz: https://doi.org/10.21014/ACTA_IMEKO.V9I3.762
  • Pracoviště: Katedra měření
  • Anotace:
    To reduce the construction costs and to increase energy savings and the indoor environmental quality in a woodhouse, an energy consumption measuring system for diagnostics of thermal and technical properties of buildings envelope has been developed. At present, the vast majority of calculations for the thermal and technical characteristics of buildings are based on simple mathematical models of building envelope behavior derived primarily from the thermal transmittance of individual materials. However, the thermal transmittance is measured in a stable laboratory environment. Therefore, the measured values may not match the real behavior of materials in continually changing climatic conditions. The Energy Consumption Measuring System has been installed to seven woodhouses in different climatic areas to diagnose the thermal and technical properties of a building's envelope. The power consumption, temperature, and humidity of the air and of the wood, CO2 concentration, temperature of the individual layers of the envelope sandwich structure, and wind speed and direction are measured. Thanks to the sets of real measurements of the thermal and technical behavior, the actual dependence of the indoor environment quality on the outdoor climatic conditions can be obtained. The presented system can reveal imperfections in heat capacity and hygroscopicity of materials used for the construction of a woodhouse. Based on this measurement, the materials can be revised to save the construction costs, energy savings, and to increase the indoor environment quality, together with environmental impact reduction.

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.

System for Acoustic Detection

  • Pracoviště: Katedra měření
  • Anotace:
    At present, acoustic detection techniques of gunshots (gunshot detection) are increasingly being used not only for military applications but also for civilian purposes. Detection, localization, and classification of gunshots employing acoustic detection is perspective alternative to visual detection, which is commonly used. In certain situations, to detect a source of a gunshot, an automatic acoustic detection system may be preferable. This paper presents a system for acoustic detection, which can detect localize and classify acoustic events such as gunshots. Tested firearms are 9 mm short gun, 6.35 mm short gun, .22 short gun, and .22 rifle gun with various subsonic and supersonic ammunition. As “false alarms,” sets of different impulse acoustic events like door slams, breaking glass, etc. have been used. To successfully classify the tested acoustic signals, Continuous Wavelet and Mel Frequency Transformation methods have been used for the signal processing, and the fully two-layer connected neural network has been implemented. The results show that the acoustic detector can be used for reliable gunshot detection, localization, and classification.

Akustická detekce a lokalizace zdroje střelby

  • Pracoviště: Katedra měření
  • Anotace:
    V současné době jsou techniky detekce akustických impulzních signálů (detekce výstřelů) čím dál více využívány nejen pro vojenské aplikace, ale také pro civilní účely. S přibývajícími útoky ve školách, kampusech, nákupních centrech nebo v nemocnicích vzniká požadavek automatického rozpoznání střelby i jinými metodami než kamerovými systémy ve spojení s operátorem. Lokalizace a klasifikace střelby pomocí akustické detekce je proto z hlediska bezpečnosti obyvatelstva čím dál tím důležitější.

Characterization of the Solar Cells Under the Real Conditions

  • Pracoviště: Katedra měření
  • Anotace:
    With an increasing number of wearable devices of all shapes and forms, which are equipped with new types of sensors to count steps, measure heart rate or even detect a fall, there is a requirement for more energy. Energy harvesting is one of the possible ways to increase the energy capability of such devices. The solar cells offer a renewable green source of energy to increase the power of wearable devices. At present, there is no binding uniform methodology for Solar Cell characterization under real light conditions of everyday life. The article presents a daily generation of energy in various daily life activity such as walking, car driving or office working with indoor illuminating. The solar cell, working in Maximum Power Point Tracking, attached to the hand of the person has been used. The presented results show expected amounts of generated energy in everyday life activities, which could be used for a better characterization of solar cells in the future.

Laboratory exercise of digital measurement system based on Modbus protocol used for indoor environment monitoring

  • DOI: 10.1117/12.2527892
  • Odkaz: https://doi.org/10.1117/12.2527892
  • Pracoviště: Katedra měření
  • Anotace:
    The proposed laboratory exercise is focused on the measurement of indoor environment quality (temperature, humidity, CO2 concentration) using digital measurement system based on Modbus protocol. Students acquire practical knowledge and general principles of the Modbus protocol, configuration and communication principles of smart sensors and measurement of temperature, humidity, CO2 concentration together with power consumption. The benefit for students in comparison with the old task is the improved quality of the laboratory task in the area of measurement circuits and fieldbus communication with the focus on industrial application.

Smart Acoustic Sensor

  • DOI: 10.1109/RTSI.2019.8895591
  • Odkaz: https://doi.org/10.1109/RTSI.2019.8895591
  • Pracoviště: Katedra měření
  • Anotace:
    To automatically detect dangerous situations in public areas, systems based on visual detection are the most commonly used. In certain situations, to detect a source of danger, an automatic acoustic detection system may be preferable. This paper presents a smart acoustic sensor system, which automatically detects acoustic pulse events, such as gunshots, in public places, and localizes the position of the acoustic source. Tested firearms are 9 mm short gun, 6.35 mm short gun, .22 short gun with various subsonic and supersonic ammunition. Various sounds like door slams, human screams, etc. represent false alarms.

Solar Panel and Harvesting Systems - Use Cases, Measurements and Reporting Methodologies

  • Pracoviště: Katedra měření
  • Anotace:
    With an increasing number of wearable devices of all shapes and forms, which are equipped with new types of sensors to count steps, measure heart rate or even detect a fall, there is a requirement for more energy. Energy harvesting is one of the possible ways to increase the energy capability of such devices. The solar cells offer a renewable green source of energy to increase the power of wearable devices. At present, there is no binding uniform methodology for Solar Cell characterization under real light conditions of everyday life. The article presents a daily generation of energy in various daily life activity such as walking, car driving or office working with indoor illuminating. The solar cell, working in Maximum Power Point Tracking, attached to the hand of the person has been used. The presented results show expected amounts of generated energy in everyday life activities, which could be used for a better characterization of solar cells in the future.

Woodhouse Energy Consumption Measurement System for Diagnostics of Thermal and Technical Properties of Buildings Envelope

  • Autoři: Ing. Jakub Svatoš, Ph.D., prof. Ing. Jan Holub, Ph.D.,
  • Publikace: 23rd IMEKO TC4 Symposium Electrical & Electronic Measurement. Budapest: IMEKO TC4 Technical Committee on Measurement of Electrical Quantities, 2019. p. 1-5. 23. ISBN 978-606-13-5238-8.
  • Rok: 2019
  • Pracoviště: Katedra měření
  • Anotace:
    To reduce the construction costs and to increase energy savings and the indoor environmental quality in a woodhouse, an energy consumption measuring system for diagnostics of thermal and technical properties of buildings envelope is introduced. At present, the vast majority of calculations for the thermal and technical characteristics of buildings are based on simple mathematical models of building envelope behaviour derived primarily from the thermal conductivity of individual materials. However, the thermal conductivity is measured in a stable laboratory environment. Therefore, the measured values may not match the real behaviour of materials in continually changing climatic conditions. The Energy Consumption Measuring System has been installed to eight woodhouses in different climatic areas to diagnose the thermal and technical properties of buildings envelope. The power consumption, temperature, and humidity of the air and of the wood, CO2 concentration, temperature of the individual layers of the envelope sandwich structure and wind speed and direction are measured. Thanks to the sets of real measurements of the thermal and technical behaviour, the actual dependence of the indoor environment quality on the outdoor climatic conditions are obtained.

Akustická detekce střelby (nejen) v ulicích města

  • Pracoviště: Katedra měření
  • Anotace:
    V současnosti jsou techniky detekce akustických impulzních signálů, neboli detekce střelby, používány nejen ve vojenských aplikacích, ale také v civilních oblastech, jako jsou detekce střelby ve školách, kampusech, nákupních centrech nebo v nemocnicích. Detekce, lokalizace a klasifikace střelby je z hlediska bezpečnosti obyvatelstva čím dál tím důležitější.

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.

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.

Metal Discrimination Using Time Domain Processed Sinc Signal

  • Autoři: Ing. Jakub Svatoš, Ph.D.,
  • Publikace: BEC 2016 15th Biennial Baltic Electronics Conference (BEC). USA: IEEE Computer Society, 2016. pp. 151-154. ISSN 1736-3705. ISBN 978-1-5090-1393-7.
  • Rok: 2016
  • DOI: 10.1109/BEC.2016.7743751
  • Odkaz: https://doi.org/10.1109/BEC.2016.7743751
  • Pracoviště: Katedra měření
  • Anotace:
    This paper describes the application and time domain signal processing of polyharmonic sinc function as an excitation signal for eddy current metal detectors. Limitations of all conventional eddy current metal detectors or induction devices in general reside in its limited ability to discriminate or unequivocally identify detected materials. To better identify or classify materials, the excitation signal and its following processing in the detector should be done. The paper is focused on the processing of the polyharmonic sinc signal in the time domain in order to improve the discrimination ability into ferromagnetic and non-ferromagnetic materials. Processing of polyharmonic signal in time domain bring a fast and undemanding method. Spheres of different diameters and from different ferromagnetic and nonferromagnetic materials were used as specimens. Experimental measurements were processed in time domain only – standard integral parameters of the signal were used for target identification.

Single-tone and Polyharmonic Eddy Current Metal Detection and Non-Destructive Testing Education Software

  • Autoři: Ing. Jakub Svatoš, Ph.D.,
  • Publikace: Journal of Physics: Conference Series. Bristol: Institute of Physics Publishing, 2016. Journal of Physics: Conference Series. ISSN 1742-6596.
  • Rok: 2016
  • DOI: 10.1088/1742-6596/772/1/012052
  • Odkaz: https://doi.org/10.1088/1742-6596/772/1/012052
  • Pracoviště: Katedra měření
  • Anotace:
    This paper describes the design of a measuring chain for polyharmonic metal detectors used for education in laboratory exercises at Czech Technical University in Prague, Faculty of Electrical Engineering, Department of Measurement. The Measuring chain is composed of DDS signal generator, Digitiser and PC with software programmed in Labview. Eddy current principles or more specifically eddy current metal detectors are an important part of nondestructive testing, instrumentations and measurement. A short introduction to the background and principles of eddy current metal detectors are presented. Next part of the article deals with a brief description of the most common methods, as well as, non-traditional polyharmonic methods for eddy current metal detection. The following part contains an implementation of the proposed algorithms in LabVIEW graphical programming language. Finally, the created program for education of eddy current metal detectors and results obtained on the metal detector ATMID are discussed.

Polyharmonic Metal Detector

  • Autoři: Ing. Jakub Svatoš, Ph.D., Linda, M.
  • Publikace: 14th International Scientific Conference Engineering for Rural Development Proceedings. Jelgava: Latvia University of Agriculture, 2015. pp. 817-822. ISSN 1691-3043.
  • Rok: 2015
  • Pracoviště: Katedra měření
  • Anotace:
    This article deals with usage of polyharmonic signals to metal detection and discrimination. A substantial problem of all conventional eddy current metal detectors (induction devices at general) is in limited possibilities of identification of detected objects. The excitation signal and signal processing in the detector should be done in a way to better characterize the detected object. Usage of polyharmonic excitation signal and processing of the signal brings an opportunity to improve the detection ability. Suitable polyharmonic excitation signal is sin(x)/x – sinc signal. Experimental measurements were processed in frequency domain using Discrete Fourier Transformation. Amplitude and phase spectra together with polar graphs are presented. As experimental targets different ferromagnetic and non-ferromagnetic materials were used.

Intelligent Metal Detector

  • Autoři: Nováček, P., Ing. Jakub Svatoš, Ph.D.,
  • Publikace: IC-MAST - 2nd International Conference on Materials and Applications for Sensors and Transducers. Zürich: Transtech Publications, 2013, pp. 133-136. Advanced Materials Research. ISSN 1013-9826.
  • Rok: 2013
  • DOI: 10.4028/www.scientific.net/KEM.543.133
  • Odkaz: https://doi.org/10.4028/www.scientific.net/KEM.543.133
  • Pracoviště: Katedra měření
  • Anotace:
    Humanitarian demining is a matter of high interest, but metal contamination and magnetic soils reduce the sensitivity of metal detectors. The soil contamination also increases the numbers of false alarms which, in some areas, account for as much as 99.9 % of all alarms. The decrease of false alarms is therefore attractive. Our solution is capable to be adapted and utilized with current professional metal detectors. Essentially it consists of several modules with modular structure, where the master module is always necessary in all applications and the navigation module has to be connected in cases where position estimation is required. Searching part of the detector is able to work in continuous wave mode with variable excitation signal and the possibility to utilize more carrier frequencies. Furthermore, the modular structure can use different search heads available on the market as well as heads developed for special purposes. The modular metal and mine detector described is capable to detect not only unexploded ordnance and explosive remnants of wars, but also pipes and wires in walls and floors indoor which is useful property during not only buildings reconstructions.

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.

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.

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.

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.

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.

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.

Za stránku zodpovídá: Ing. Mgr. Radovan Suk