Pub Date : 2007-04-24DOI: 10.1109/RADIOELEK.2007.371649
M. Sloboda, V. Rícný
The article briefly describes parameters of transmission channel and parameters of measuring the transmission and the sources of possible transmitting errors. In the first part, types of the transmission channels, the theoretic planning of the signal coverage and causes of simulating of ideal transmission channels are shown. The next part deals with the types of errors and the causes of errors in the transmission channel. This enumeration includes the computing of some error parameters. The last part of the article deals with a possible multi-path propagation of the digital television signal from transmitter to receiver. There is briefly explained a prevention of multipath reception by using a guard interval.
{"title":"Influence of Transmission Channel on DVB-T Signal","authors":"M. Sloboda, V. Rícný","doi":"10.1109/RADIOELEK.2007.371649","DOIUrl":"https://doi.org/10.1109/RADIOELEK.2007.371649","url":null,"abstract":"The article briefly describes parameters of transmission channel and parameters of measuring the transmission and the sources of possible transmitting errors. In the first part, types of the transmission channels, the theoretic planning of the signal coverage and causes of simulating of ideal transmission channels are shown. The next part deals with the types of errors and the causes of errors in the transmission channel. This enumeration includes the computing of some error parameters. The last part of the article deals with a possible multi-path propagation of the digital television signal from transmitter to receiver. There is briefly explained a prevention of multipath reception by using a guard interval.","PeriodicalId":446406,"journal":{"name":"2007 17th International Conference Radioelektronika","volume":"114 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125341608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-04-24DOI: 10.1109/RADIOELEK.2007.371492
F. Schadt, F. Mohr
This investigation was stimulated by the search for a simple and easy-to-apply method for measuring the movement of a car safety belt under a crash. Conventional methods would consist of gluing an incremental barcode-like strip on the belt, observing it with a reflective optical sensor, and counting the periods occurring while the belt is pulled out. However, as the woven structure of the belt constitutes a quite well-defined periodic texture by itself, the question arises if it is possible to determine the velocity from observing this. The method would then require imaging the texture to a suitably designed transmitting reference mask and evaluating the periodical signal observed behind the mask while the belt is moving. Mathematically, the proposed procedure can be called an optical spatial filter (OSF) technique. Of course, when applying OSF technique for velocity measurements of periodic objects it is vital to adapt the spatial filter closely to the moving object. While objects with a random surface or texture are quite easy to deal with, those with a periodic surface need special consideration. This investigation is aimed to explain the necessary considerations and to present techniques for suitably designing optical spatial filters.
{"title":"Spatial Filter Design Techniques with Applications in Optical Velocity Measurement","authors":"F. Schadt, F. Mohr","doi":"10.1109/RADIOELEK.2007.371492","DOIUrl":"https://doi.org/10.1109/RADIOELEK.2007.371492","url":null,"abstract":"This investigation was stimulated by the search for a simple and easy-to-apply method for measuring the movement of a car safety belt under a crash. Conventional methods would consist of gluing an incremental barcode-like strip on the belt, observing it with a reflective optical sensor, and counting the periods occurring while the belt is pulled out. However, as the woven structure of the belt constitutes a quite well-defined periodic texture by itself, the question arises if it is possible to determine the velocity from observing this. The method would then require imaging the texture to a suitably designed transmitting reference mask and evaluating the periodical signal observed behind the mask while the belt is moving. Mathematically, the proposed procedure can be called an optical spatial filter (OSF) technique. Of course, when applying OSF technique for velocity measurements of periodic objects it is vital to adapt the spatial filter closely to the moving object. While objects with a random surface or texture are quite easy to deal with, those with a periodic surface need special consideration. This investigation is aimed to explain the necessary considerations and to present techniques for suitably designing optical spatial filters.","PeriodicalId":446406,"journal":{"name":"2007 17th International Conference Radioelektronika","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121315831","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-04-24DOI: 10.1109/RADIOELEK.2007.371416
D. Biolek, V. Biolková, Z. Kolka
A generalization of the model of PWM switch according to Dijk et al. for averaged modeling of switched DC-DC converters is proposed. This model now includes the on-resistance of the active switch, and the forward voltage drop and the differential resistance of diode-type passive switch. The way this model is compiled allows for the influence of parasitic ESRs of the capacitors in the circuit such that the resulting equations are equivalent to the averaged state space equations. The procedure of PSPICE modeling and the results of computer simulation of boost converter are shown.
{"title":"SPICE Modeling of Switched DC-DC Converters via Generalized Model of PWM Switch","authors":"D. Biolek, V. Biolková, Z. Kolka","doi":"10.1109/RADIOELEK.2007.371416","DOIUrl":"https://doi.org/10.1109/RADIOELEK.2007.371416","url":null,"abstract":"A generalization of the model of PWM switch according to Dijk et al. for averaged modeling of switched DC-DC converters is proposed. This model now includes the on-resistance of the active switch, and the forward voltage drop and the differential resistance of diode-type passive switch. The way this model is compiled allows for the influence of parasitic ESRs of the capacitors in the circuit such that the resulting equations are equivalent to the averaged state space equations. The procedure of PSPICE modeling and the results of computer simulation of boost converter are shown.","PeriodicalId":446406,"journal":{"name":"2007 17th International Conference Radioelektronika","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126948854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-04-24DOI: 10.1109/RADIOELEK.2007.371651
M. Stork
Frequency synthesizers are an essential part of any modern transceiver system. They generate clock and oscillator signals needed for up and down conversion. Today's communication standards demand both high frequency accuracy and fast frequency settling. The fine frequency resolution, low spurious signals, accuracy and stability are most important for these devices. In this paper, the new frequency synthesizer architecture based on direct synthesis and coincidence mixer is presented. The simulation results are also shown.
{"title":"Frequency Synthesizer Based on Coincidence Mixer","authors":"M. Stork","doi":"10.1109/RADIOELEK.2007.371651","DOIUrl":"https://doi.org/10.1109/RADIOELEK.2007.371651","url":null,"abstract":"Frequency synthesizers are an essential part of any modern transceiver system. They generate clock and oscillator signals needed for up and down conversion. Today's communication standards demand both high frequency accuracy and fast frequency settling. The fine frequency resolution, low spurious signals, accuracy and stability are most important for these devices. In this paper, the new frequency synthesizer architecture based on direct synthesis and coincidence mixer is presented. The simulation results are also shown.","PeriodicalId":446406,"journal":{"name":"2007 17th International Conference Radioelektronika","volume":"177 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134502326","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-04-24DOI: 10.1109/RADIOELEK.2007.371420
T. Dostil, V. Axman
The paper deals with the classical three-port current conveyors so called second generation one (CC II). A unique application of the CC II is discussed, when the terminals Y and Z are connected together. Using this way a negative impedance converter is obtained as a suitable building block in applications given there. Specially a synthesis of the several continuous-time ARC biquadratic (second-order) filters, having or not transmission zero, is given there too.
{"title":"Current Conveyor CC II with Connected Ports Y-Z","authors":"T. Dostil, V. Axman","doi":"10.1109/RADIOELEK.2007.371420","DOIUrl":"https://doi.org/10.1109/RADIOELEK.2007.371420","url":null,"abstract":"The paper deals with the classical three-port current conveyors so called second generation one (CC II). A unique application of the CC II is discussed, when the terminals Y and Z are connected together. Using this way a negative impedance converter is obtained as a suitable building block in applications given there. Specially a synthesis of the several continuous-time ARC biquadratic (second-order) filters, having or not transmission zero, is given there too.","PeriodicalId":446406,"journal":{"name":"2007 17th International Conference Radioelektronika","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131238371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-04-24DOI: 10.1109/RADIOELEK.2007.371655
Ĺ. Syrová, R. Ravas, J. Grman
The contribution treats the topic of processing the experimentally gained information on the properties of optically transparent polymeric foils. Schlieren optical system was used to examine and visualize refractive index distribution. Experimental results of statistical and frequency approach to classification of different types of polymeric foils into classes are compared.
{"title":"Comparison between Statistical and Frequency Approach to Classification of Visualized Transparent Polymeric Foils","authors":"Ĺ. Syrová, R. Ravas, J. Grman","doi":"10.1109/RADIOELEK.2007.371655","DOIUrl":"https://doi.org/10.1109/RADIOELEK.2007.371655","url":null,"abstract":"The contribution treats the topic of processing the experimentally gained information on the properties of optically transparent polymeric foils. Schlieren optical system was used to examine and visualize refractive index distribution. Experimental results of statistical and frequency approach to classification of different types of polymeric foils into classes are compared.","PeriodicalId":446406,"journal":{"name":"2007 17th International Conference Radioelektronika","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130975370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-04-24DOI: 10.1109/RADIOELEK.2007.371656
T. Tokar, D. Levický
Digital watermarking has been proposed as a method for discouraging illegal copying and distribution of copyrighted material. Many proposed methods in digital watermarking are not robust against geometrical attacks. This paper presents a new algorithm that improves the robustness of watermarking methods against geometrical operations. We briefly described affine transformation and its major properties too. Finally, we also present results, which verify the enhanced robustness of proposed algorithm against geometrical attacks.
{"title":"Robust Watermarking of Gray Scale Images by Using Synchronization Templates","authors":"T. Tokar, D. Levický","doi":"10.1109/RADIOELEK.2007.371656","DOIUrl":"https://doi.org/10.1109/RADIOELEK.2007.371656","url":null,"abstract":"Digital watermarking has been proposed as a method for discouraging illegal copying and distribution of copyrighted material. Many proposed methods in digital watermarking are not robust against geometrical attacks. This paper presents a new algorithm that improves the robustness of watermarking methods against geometrical operations. We briefly described affine transformation and its major properties too. Finally, we also present results, which verify the enhanced robustness of proposed algorithm against geometrical attacks.","PeriodicalId":446406,"journal":{"name":"2007 17th International Conference Radioelektronika","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131640996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-04-24DOI: 10.1109/RADIOELEK.2007.371467
J. Húska, P. Kulla
In this paper a new fast block based motion estimation algorithm is presented. The new algorithm is based on well known diamond search with incorporated recursive and multi stage techniques. Its main benefit against other existing fast block based motion estimation algorithms is the ability to overcome the ambiguity in motion estimation (aperture problem, indeterminate flow vector in regions with constant brightness) that yield from optical flow equation. These problems are eliminated due to our new search strategy which employs fact that the image pixels corresponding to the same object projection all account similar movement. The algorithm with combined recursive and multi stage techniques is capable of estimating vector motion fields with eliminated chaotic motion fields and approaching true motion field.
{"title":"A New Recursive Search with Multi Stage Approach for Fast Block Based True Motion Estimation","authors":"J. Húska, P. Kulla","doi":"10.1109/RADIOELEK.2007.371467","DOIUrl":"https://doi.org/10.1109/RADIOELEK.2007.371467","url":null,"abstract":"In this paper a new fast block based motion estimation algorithm is presented. The new algorithm is based on well known diamond search with incorporated recursive and multi stage techniques. Its main benefit against other existing fast block based motion estimation algorithms is the ability to overcome the ambiguity in motion estimation (aperture problem, indeterminate flow vector in regions with constant brightness) that yield from optical flow equation. These problems are eliminated due to our new search strategy which employs fact that the image pixels corresponding to the same object projection all account similar movement. The algorithm with combined recursive and multi stage techniques is capable of estimating vector motion fields with eliminated chaotic motion fields and approaching true motion field.","PeriodicalId":446406,"journal":{"name":"2007 17th International Conference Radioelektronika","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132546336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-04-24DOI: 10.1109/RADIOELEK.2007.371450
L. Jelínek, J. Macháč, J. Zehentner
The permittivity, permeability and conductivity of a material characterize its ability to interact with an electromagnetic field. In nature, the magnitudes of these three quantities are restricted mostly to positive values. In contrast, metamaterials are artificially produced composite media exhibiting electromagnetic responses that natural materials do not provide. They enable the three constitutive parameters to be cast down to negative values. Nowadays, electromagnetic metamaterials is a rapidly growing research domain involving electromagnetism, microwave and millimeter wave technology, optics, material technology and nanotechnology. There are prospects for many challenging practical applications. A historical survey of the evolution of metamaterials from the earliest assumptions until the current state of the art introduces discussion upon the metamaterials, description of their characteristics and behavior. Metamaterials are known in two forms. An inherent metamaterial is a real 3D solid volumetric medium. 1D or 2D planar circuits are the second version of metamaterials. The first form is characterized by field theory, while the second form utilizes transmission line theory. Manifold applications of guided waves, radiated waves, new microwave circuits, devices and structures will be discussed from the engineering point of view. There is a brief report on the authors' innovative findings. This involves both theoretical and experimental results that have been achieved in recent years. In particular, it concerns the utilization of split ring resonators in negative permeability metamaterials, the concept and the production of an isotropic negative permeability medium, an isotropic negative permittivity medium, CPW supporting propagation of a left-handed wave, and wire media exhibiting negative permittivity. Finally, prospects for further developments in this interesting field are presented.
{"title":"Metamaterials - A Challenge for Contemporary Advanced Technology","authors":"L. Jelínek, J. Macháč, J. Zehentner","doi":"10.1109/RADIOELEK.2007.371450","DOIUrl":"https://doi.org/10.1109/RADIOELEK.2007.371450","url":null,"abstract":"The permittivity, permeability and conductivity of a material characterize its ability to interact with an electromagnetic field. In nature, the magnitudes of these three quantities are restricted mostly to positive values. In contrast, metamaterials are artificially produced composite media exhibiting electromagnetic responses that natural materials do not provide. They enable the three constitutive parameters to be cast down to negative values. Nowadays, electromagnetic metamaterials is a rapidly growing research domain involving electromagnetism, microwave and millimeter wave technology, optics, material technology and nanotechnology. There are prospects for many challenging practical applications. A historical survey of the evolution of metamaterials from the earliest assumptions until the current state of the art introduces discussion upon the metamaterials, description of their characteristics and behavior. Metamaterials are known in two forms. An inherent metamaterial is a real 3D solid volumetric medium. 1D or 2D planar circuits are the second version of metamaterials. The first form is characterized by field theory, while the second form utilizes transmission line theory. Manifold applications of guided waves, radiated waves, new microwave circuits, devices and structures will be discussed from the engineering point of view. There is a brief report on the authors' innovative findings. This involves both theoretical and experimental results that have been achieved in recent years. In particular, it concerns the utilization of split ring resonators in negative permeability metamaterials, the concept and the production of an isotropic negative permeability medium, an isotropic negative permittivity medium, CPW supporting propagation of a left-handed wave, and wire media exhibiting negative permittivity. Finally, prospects for further developments in this interesting field are presented.","PeriodicalId":446406,"journal":{"name":"2007 17th International Conference Radioelektronika","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115934604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-04-24DOI: 10.1109/RADIOELEK.2007.371417
Z. Brezović, V. Kudják
This paper introduces a new method for extraction parameters of quartz equivalent circuit. Temperature dependencies of parameters in extended temperature range were carried out by measurement by a six port reflectometer. The algorithm was implemented in Matlab language with programmed graphical user interface.
{"title":"Extraction Parameters of Quartz Equivalent Circuit in Matlab","authors":"Z. Brezović, V. Kudják","doi":"10.1109/RADIOELEK.2007.371417","DOIUrl":"https://doi.org/10.1109/RADIOELEK.2007.371417","url":null,"abstract":"This paper introduces a new method for extraction parameters of quartz equivalent circuit. Temperature dependencies of parameters in extended temperature range were carried out by measurement by a six port reflectometer. The algorithm was implemented in Matlab language with programmed graphical user interface.","PeriodicalId":446406,"journal":{"name":"2007 17th International Conference Radioelektronika","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122787567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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