Pub Date : 2007-09-01DOI: 10.1109/ICECOM.2007.4544492
D. Cermak, J. Pidanic, V. Schejbal
The propagation of signals for ultra wide band (UWB) systems is analyzed. Signals can be substantially affected due to electromagnetic wave propagation through walls or similar obstacles. New experimental results and numerical simulations for frequency band from 4 to 8 GHz are analyzed and compared. That is briefly compared with the time domain experiments, which have been performed using very short pulses. Experiments performed for frequency and time domains demonstrated that the numerical simulations, which are very fast, could be reliable, when suitable wall parameters are used. Some questions concerning electromagnetic compatibility (EMC) are briefly mentioned.
{"title":"Through-Wall Propagation Measurements","authors":"D. Cermak, J. Pidanic, V. Schejbal","doi":"10.1109/ICECOM.2007.4544492","DOIUrl":"https://doi.org/10.1109/ICECOM.2007.4544492","url":null,"abstract":"The propagation of signals for ultra wide band (UWB) systems is analyzed. Signals can be substantially affected due to electromagnetic wave propagation through walls or similar obstacles. New experimental results and numerical simulations for frequency band from 4 to 8 GHz are analyzed and compared. That is briefly compared with the time domain experiments, which have been performed using very short pulses. Experiments performed for frequency and time domains demonstrated that the numerical simulations, which are very fast, could be reliable, when suitable wall parameters are used. Some questions concerning electromagnetic compatibility (EMC) are briefly mentioned.","PeriodicalId":446406,"journal":{"name":"2007 17th International Conference Radioelektronika","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129334375","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.2007.371475
P. Pavelka, J. Krajňák, P. Galajda, D. Kocur
Multi-carrier code division multiple access (MC-CDMA) is a powerful modulation technique that is being considered in many emerging broadband communication systems. MC-CDMA systems based on OFDM are high sensitive to nonlinear amplification what results in inefficient use of power amplifiers. In a microstatistic MUD (MSF-MUD) has been proposed for performance improvement of MC-CDMA degraded by nonlinear amplifiers. In this paper, a new efficient design procedure of MSF-MUD for nonlinearly distorted symbols of MC-CDMA based on M-symbol QAM modulation is proposed. This method is based on the analysis and change tracking of the M-symbol QAM signal constellations of non-distorted and nonlinearly distorted MC-CDMA symbols by using a training sequence. The results obtained in this paper confirm, that the MSF-MUD clearly overcomes a linear MUD at the outlined scenario whereas MSF-MUD designed by the new method described in this paper is able to provide almost the same performance than that of optimum MSF-MUD.
{"title":"Efficient Design Procedure of Microstatistic Multi-user Detector for Nonlinearly Distorted MC-CDMA","authors":"P. Pavelka, J. Krajňák, P. Galajda, D. Kocur","doi":"10.1109/RADIOELEK.2007.371475","DOIUrl":"https://doi.org/10.1109/RADIOELEK.2007.371475","url":null,"abstract":"Multi-carrier code division multiple access (MC-CDMA) is a powerful modulation technique that is being considered in many emerging broadband communication systems. MC-CDMA systems based on OFDM are high sensitive to nonlinear amplification what results in inefficient use of power amplifiers. In a microstatistic MUD (MSF-MUD) has been proposed for performance improvement of MC-CDMA degraded by nonlinear amplifiers. In this paper, a new efficient design procedure of MSF-MUD for nonlinearly distorted symbols of MC-CDMA based on M-symbol QAM modulation is proposed. This method is based on the analysis and change tracking of the M-symbol QAM signal constellations of non-distorted and nonlinearly distorted MC-CDMA symbols by using a training sequence. The results obtained in this paper confirm, that the MSF-MUD clearly overcomes a linear MUD at the outlined scenario whereas MSF-MUD designed by the new method described in this paper is able to provide almost the same performance than that of optimum MSF-MUD.","PeriodicalId":446406,"journal":{"name":"2007 17th International Conference Radioelektronika","volume":"10 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":"115453739","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.2007.371430
V. Kudják, Z. Brezović
A new version of RF oscillator with high linearity (THD<1%) and wide zone of adjusting its amplitude (min. 40 dB) is presented in this contribution. Oscillator is designed for single and quickly measurement of non-linearity effects in varactor-tuned LC resonators, and it is usable in frequency band from LF up to 50 MHz. Active part of the oscillator consist of high-speed OA of type VFB (voltage feedback), or CVB (current feedback) and resistive feedback circuit. Herein are presented analytical relationships derived for parameters input characteristics for both VFB OA and CVB OA respectively. OA with positive feedback has in the centre its input characteristics negative resistance, which give the possibility to compensate losses in parallel LC resonator. For simple and effective control of the oscillation amplitude is used backward biased diode detector with control voltage. In contributions are also presented measured parameters of the oscillator and there are given some examples of measured tuning characteristics with varactors.
{"title":"A Flexible Oscillator for Measurement of Varactor-Tuned Resonators","authors":"V. Kudják, Z. Brezović","doi":"10.1109/RADIOELEK.2007.371430","DOIUrl":"https://doi.org/10.1109/RADIOELEK.2007.371430","url":null,"abstract":"A new version of RF oscillator with high linearity (THD<1%) and wide zone of adjusting its amplitude (min. 40 dB) is presented in this contribution. Oscillator is designed for single and quickly measurement of non-linearity effects in varactor-tuned LC resonators, and it is usable in frequency band from LF up to 50 MHz. Active part of the oscillator consist of high-speed OA of type VFB (voltage feedback), or CVB (current feedback) and resistive feedback circuit. Herein are presented analytical relationships derived for parameters input characteristics for both VFB OA and CVB OA respectively. OA with positive feedback has in the centre its input characteristics negative resistance, which give the possibility to compensate losses in parallel LC resonator. For simple and effective control of the oscillation amplitude is used backward biased diode detector with control voltage. In contributions are also presented measured parameters of the oscillator and there are given some examples of measured tuning characteristics with varactors.","PeriodicalId":446406,"journal":{"name":"2007 17th International Conference Radioelektronika","volume":"43 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":"127136375","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.2007.371679
J. Jilková, Z. Lukeš, Z. Raida
This paper deals with modeling of the ultra-wideband planar antennas with coplanar feeding in the commercial available programs. After a brief summary of the basic principles of high-frequency structures modeling, a specific design of wideband antennas on two different substrates is shown. The antennas are modeled in CST Microwave Studio and Zeland IE3D. Simulation results are compared to measured data.
{"title":"Modeling of Ultra-wideband Coplanar Patch Antennas","authors":"J. Jilková, Z. Lukeš, Z. Raida","doi":"10.1109/RADIOELEK.2007.371679","DOIUrl":"https://doi.org/10.1109/RADIOELEK.2007.371679","url":null,"abstract":"This paper deals with modeling of the ultra-wideband planar antennas with coplanar feeding in the commercial available programs. After a brief summary of the basic principles of high-frequency structures modeling, a specific design of wideband antennas on two different substrates is shown. The antennas are modeled in CST Microwave Studio and Zeland IE3D. Simulation results are compared to measured data.","PeriodicalId":446406,"journal":{"name":"2007 17th International Conference Radioelektronika","volume":"2012 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":"127403777","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.2007.371706
T. Drizdal, P. Togni, J. Vrba
Nowadays hyperthermia is one of the possible cancer treatment method used in combination with classical therapies in several countries in the world. In this article we described the designed and optimization of a microstrip type applicator for the treatment of superficial diseases. The optimization was made in order to obtain a more uniform SAR distribution, which is one of the requirements to achieve a good thermotherapy treatment.
{"title":"Modified Microstrip Ring Applicator for Superficial Hyperthermia","authors":"T. Drizdal, P. Togni, J. Vrba","doi":"10.1109/RADIOELEK.2007.371706","DOIUrl":"https://doi.org/10.1109/RADIOELEK.2007.371706","url":null,"abstract":"Nowadays hyperthermia is one of the possible cancer treatment method used in combination with classical therapies in several countries in the world. In this article we described the designed and optimization of a microstrip type applicator for the treatment of superficial diseases. The optimization was made in order to obtain a more uniform SAR distribution, which is one of the requirements to achieve a good thermotherapy treatment.","PeriodicalId":446406,"journal":{"name":"2007 17th International Conference Radioelektronika","volume":"26 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":"125922721","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.2007.371684
A. Kusiek, P. Kowalczyk, J. Mazur
In this paper the new technique of analysis of an arbitrary configuration of metallic elliptical objects is presented. The proposed method is based on T-matrix representation of elliptical object in cylindrical coordinates system. The total scattered field is computed with usage iterative scattering procedure (ISP). The numerical results are compared with once obtained from commercial software and a very good agreement was achieved.
{"title":"Investigations of Scattering from Arbitrary Configuration of Elliptical Obstacles","authors":"A. Kusiek, P. Kowalczyk, J. Mazur","doi":"10.1109/RADIOELEK.2007.371684","DOIUrl":"https://doi.org/10.1109/RADIOELEK.2007.371684","url":null,"abstract":"In this paper the new technique of analysis of an arbitrary configuration of metallic elliptical objects is presented. The proposed method is based on T-matrix representation of elliptical object in cylindrical coordinates system. The total scattered field is computed with usage iterative scattering procedure (ISP). The numerical results are compared with once obtained from commercial software and a very good agreement was achieved.","PeriodicalId":446406,"journal":{"name":"2007 17th International Conference Radioelektronika","volume":"104 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":"115578676","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.2007.371657
J. Turán, Ľ. Ovseník, S. Marchevsky
The proposed paper deals with image processing using invertible rapid transform (IRT). A software tool for image processing using IRT is presented.
提出了一种基于可逆快速变换(IRT)的图像处理方法。介绍了一种利用IRT进行图像处理的软件工具。
{"title":"Image Processing with Invertible Rapid Transform","authors":"J. Turán, Ľ. Ovseník, S. Marchevsky","doi":"10.1109/RADIOELEK.2007.371657","DOIUrl":"https://doi.org/10.1109/RADIOELEK.2007.371657","url":null,"abstract":"The proposed paper deals with image processing using invertible rapid transform (IRT). A software tool for image processing using IRT is presented.","PeriodicalId":446406,"journal":{"name":"2007 17th International Conference Radioelektronika","volume":"9 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":"114442324","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.2007.371456
J. Cerquides
In this paper we present a system designed to detect, identify and track commercial segments transmitted by a radio station. The program is entirely written in Visual C++ and uses state of the art audio fingerprinting technologies to achieve a great performance, being able to operate several times faster than real time while keeping a moderate computational load.
{"title":"A Real Time Audio Fingerprinting System for Advertisement Tracking and Reporting in FM Radio","authors":"J. Cerquides","doi":"10.1109/RADIOELEK.2007.371456","DOIUrl":"https://doi.org/10.1109/RADIOELEK.2007.371456","url":null,"abstract":"In this paper we present a system designed to detect, identify and track commercial segments transmitted by a radio station. The program is entirely written in Visual C++ and uses state of the art audio fingerprinting technologies to achieve a great performance, being able to operate several times faster than real time while keeping a moderate computational load.","PeriodicalId":446406,"journal":{"name":"2007 17th International Conference Radioelektronika","volume":"47 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":"116823099","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.2007.371491
R. Ridzon, D. Levický
The geometrical attacks are still open problem for many digital watermarking algorithms used in present time. Most of geometrical attacks can be described by using affine transforms. This article deals with digital watermarking in images robust against the affine transformations. The new approach to improve robustness against geometrical attacks is presented. The discrete Fourier transform and log-polar mapping is used for watermark embedding and for watermark detection. Some attacks against the embedded watermarks are performed and the results are given.
{"title":"Log-polar Mapping in Robust Digital Image Watermarking","authors":"R. Ridzon, D. Levický","doi":"10.1109/RADIOELEK.2007.371491","DOIUrl":"https://doi.org/10.1109/RADIOELEK.2007.371491","url":null,"abstract":"The geometrical attacks are still open problem for many digital watermarking algorithms used in present time. Most of geometrical attacks can be described by using affine transforms. This article deals with digital watermarking in images robust against the affine transformations. The new approach to improve robustness against geometrical attacks is presented. The discrete Fourier transform and log-polar mapping is used for watermark embedding and for watermark detection. Some attacks against the embedded watermarks are performed and the results are given.","PeriodicalId":446406,"journal":{"name":"2007 17th International Conference Radioelektronika","volume":"95 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":"129580514","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.2007.371452
H. Henniger, B. Epple, D. Giggenbach
The increasing emergence of data services for mobile applications requires high-speed communication technologies. To this end, free-space optical (FSO) communications technology has the potential to outperform radio frequency (RF) systems. Within the last years, the German Aerospace Center (DLR) has performed several demonstrations of mobile FSO systems. A brief overview of these activities is given in this paper. Mobil FSO mainly suffers from relatively long link outages, produced by temporary obscured laser-beams, pointing-and tracking-errors or deep signal-fades caused by index of refraction turbulence effects. Error correction and retransmission techniques for fading mitigation are discussed in this paper. Comparison of FEC and protocol based error correction for mobile FSO transmission is presented.
{"title":"Mobil FSO Activities in Europe and Fading Mitigation Approaches","authors":"H. Henniger, B. Epple, D. Giggenbach","doi":"10.1109/RADIOELEK.2007.371452","DOIUrl":"https://doi.org/10.1109/RADIOELEK.2007.371452","url":null,"abstract":"The increasing emergence of data services for mobile applications requires high-speed communication technologies. To this end, free-space optical (FSO) communications technology has the potential to outperform radio frequency (RF) systems. Within the last years, the German Aerospace Center (DLR) has performed several demonstrations of mobile FSO systems. A brief overview of these activities is given in this paper. Mobil FSO mainly suffers from relatively long link outages, produced by temporary obscured laser-beams, pointing-and tracking-errors or deep signal-fades caused by index of refraction turbulence effects. Error correction and retransmission techniques for fading mitigation are discussed in this paper. Comparison of FEC and protocol based error correction for mobile FSO transmission is presented.","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":"128705466","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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