The requirements for RF Control Systems for the European X-FEL are not only defined in terms of the quality of field control but also with respect to operability, availability, and maintainability of the RF System, and the interfaces to other subsystems. The field control of the vector-sum of many cavities driven by one klystron in pulsed mode at high gradients is a challenging task since severe Lorentz force detuning, microphonics and beam induced field errors must be suppressed by several orders of magnitude. This is accomplished by a combination of local and global feedback and feedforward control. Sensors monitor individual cavity probe signals, and forward and reflected wave as well as the beam properties including beam energy and phase while actuators control the incident wave of the klystron and individual cavity resonance frequencies. The operability of a large llrf system requires a high degree of automation while the high availability requires robust algorithms, redundancy, and extremely reliable hardware. The maintenance of the llrf demands sophisticated on-line diagnostics for the llrf subsystems to minimize downtime.

It may be predicted now, even assuming a very conservative approach, that the next generation of the Low Level RF control systems for future accelerators will use extensively such technologies like: very fast programmable circuits equipped with DSP, embedded PC and optical communication I/O functionalities, as well as multi-gigabit optical transmission of measurement data and control signals. The paper presents the idea and realization of a gigabit synchronous data distributor designed to work in the LLRF control system of TESLA technology based X-ray FEL. The design bases on a relatively simple and cheap FPGA chip Cyclone. Commercially available SERDES (serializer/deserializer) and optical transceiver chips were applied. The optoelectronic module is embedded on the main LLRF BMB (backbone mother board). The MB provides communication with the outside computer control system, programmable chip configuration, integration with other functional modules and power supply. The hardware implementation is here described and the used software for BER (bit-error-rate) testing of the multi-gigabit optical link. The measurement results are presented. The appendix contains a comparison between the available protocols of serial data transmission for FPGA technology. This paper is a partial contribution to the next version of the SIMCON system which is expected to be released this year. The SIMCON, ver 3.0 will contain 8 channels and multi-gigabit optical transmission capability. It will be a fully modular construction.

It may be predicted now, even assuming a very conservative approach, that the next generation of the Low Level RF control systems for future accelerators will use extensively such technologies like: very fast programmable circuits equipped with DSP, embedded PC and optical communication I/O functionalities, as well as multi-gigabit optical transmission of measurement data and control signals.

The paper includes a description of predicted functionalities to be implemented in a universal motherboard (MB) for the next generation of LLRF control system for TESLA. The motherboard bases on a number of quasi-autonomous embedded executive modules. The modules are implemented in a few FPGA chips featured by the MB. The paper presents a practical design of the MB. The initial (basic) solution of the MB has the Cyclone as the chip where the board management is embedded. The board features communication modules - VME and micro, single chip PC with Ethernet. The board provides power supply for the FPGA chips. The board has fast internal communication between particular modules. The described Motherboard serves for experiments with the SIMCON 3.0 system.

The paper describes design, construction and initial measurements of an eight channel electronic LLRF device predicted for building of the control system for the W-FEL accelerator at DESY (Hamburg). The device, referred in the paper to as the SIMCON 3.0 (from the SC cavity simulator and controller) consists of a 16 layer, VME size, PCB, a large FPGA chip (VirtexII-4000 by Xilinx), eight fast ADCs and four DACs (by Analog Devices). To our knowledge, the proposed device is the first of this kind for the accelerator technology in which there was achieved (the FPGA based) DSP latency below 200 ns. With the optimized data transmission system, the overall LLRF system latency can be as low as 500 ns. The SIMCON 3.0 sub-system was applied for initial tests with the ACCl module of the VUV FEL accelerator (eight channels) and with the CHECHIA test stand (single channel), both at the DESY. The promising results with the SIMCON 3.0. encouraged us to enter the design of SIMCON 3.1. possessing 10 measurement and control channels and some additional features to be reported in the next technical note. SIMCON 3.0. is a modular solution, while SIMCON 3.1. will be an integrated board of the all-in-one type. Two design approaches - modular and all-in-one - after branching off in this version of the Simcon, will be continued.

The paper describes integrated system of hardware controller and simulator of the resonant superconducting, narrowband niobium cavity, originally considered for the TTF and TESLA in DESY, Hamburg (now predicted for the VUV and X-Ray FEL). The controller bases on a programmable circuit Xilinx VirtexII V3000 embedded on a PCB XtremeDSP Development Kit by Nallatech. The FPGA circuit configuration was done in the VHDL language. The internal hardware multiplication components, present in Virtex II chips, were used, to improve the floating point calculation efficiency. The implementation was achieved of a device working in the real time, according to the demands of the LLRF control system for the TESLA Test Facility. The device under consideration will be referred to as superconducting cavity (SCCav) SIMCON throughout this work. The following components are described here in detail: functional layer, parameter programming, foundations of control of particular blocks and monitoring of the real time processes. This note is accompanied by the one describing the DOOCS interface for the described hardware system. The interface was prepared in DOOCS and in Windows. The hardware and software of SIMCON was tested in CHECIA. The results were presented. While giving all necessary technical details required to understand the work of the integrated hardware controller and simulator and to enable its practical copying, this document is a unity with other TESLA technical notes published by the same team on the subject. Modeling was omitted, as it is addressed in detail in the quoted references.

The paper describes integrated system of hardware controller and simulator of the resonant superconducting, narrowband niobium cavity, originally considered for the TTF and TESLA in DESY, Hamburg (now predicted for the VUV and X-Ray FEL). The controller bases on a programmable circuit Xilinx VirtexII V3000 embedded on a PCB XtremeDSP Development Kit by Nallatech. The FPGA circuit configuration was done in the VHDL language. The internal hardware multiplication components, present in Virtex II chips, were used, to improve the floating point calculation efficiency. The implementation was achieved of a device working in the real time, according to the demands of the LLRF control system for the TESLA Test Facility. The device under consideration will be referred to as superconducting cavity (SCCav) SIMCON throughout this work. The following components are described here in detail: functional layer, parameter programming, foundations of control of particular blocks and monitoring of the real time processes. This note is accompanied by the one describing the DOOCS interface for the described hardware system. The interface was prepared in DOOCS and in Windows. The hardware and software of SIMCON was tested in CHECIA. The results were presented. While giving all necessary technical details required to understand the work of the integrated hardware controller and simulator and to enable its practical copying, this document is a unity with other TESLA technical notes published by the same team on the subject. Modeling was omitted, as it is addressed in detail in the quoted references.

The paper describes integrated system of hardware controller and simulator of the resonant superconducting, narrowband niobium cavity, originally considered for the TTF and TESLA in DESY, Hamburg (now predicted for the VUV and X-Ray FEL). The controller bases on a programmable circuit Xilinx VirtexII V3000 embedded on a PCB XtremeDSP Development Kit by Nallatech. The FPGA circuit configuration was done in the VHDL language. The internal hardware multiplication components, present in Virtex II chips, were used, to improve the floating point calculation efficiency. The implementation was achieved of a device working in the real time, according to the demands of the LLRF control system for the TESLA Test Facility. The device under consideration will be referred to as superconducting cavity (SCCav) SIMCON throughout this work. The following components are described here in detail: functional layer, parameter programming, foundations of control of particular blocks and monitoring of the real time processes. This note is accompanied by the one describing the DOOCS interface for the described hardware system. The interface was prepared in DOOCS and in Windows. The hardware and software of SIMCON was tested in CHECIA. The results were presented. While giving all necessary technical details required to understand the work of the integrated hardware controller and simulator and to enable its practical copying, this document is a unity with other TESLA technical notes published by the same team on the subject. Modeling was omitted, as it is addressed in detail in the quoted references.

Nowadays in VUV-FEL accelerator the superconducting cavities made of niobium are filled with electromagnetic field necessary for electron bunch acceleration. The energy for electron is delivered from the high power microwave klystron tube. According to the project requirements the power level that should be achieved from the klystrons are only possible to achieve when tube works near to the saturation point. As almost every high power amplifier also this microwave tube amplifier behavior is strongly nonlinear in this work area. In the publication the method for the klystron and whole high power chain nonlinearities characterization is described. Also some propositions for online nonlinearities measurement and for klystron linearization in the VUV-FEL accelerator are discussed.

The paper describes design and practical realization of low and high level software for laboratory purposes to control FPGA-based LLRF electronic equipment for TESLA. There is presented a universal solution for particular functional devices of the control system with FPGA chips. The paper describes architecture of software layers and programming solutions of hardware communication based on the proprietary Internal Interface (II) technology. Such a solution was used for the Superconducting Cavity Controller and Simulator (SIMCON) for TESLA experiment (Test Facility) in DESY. The examples of the build and tested software blocks were given in this paper. This documentation is a unity with TESLA Reports published in 2004 by the Elhep and describing the SIMCON hardware, ver.2.0. The paper was written in a form of a User's Manual.

The paper describes design and practical realization of low and high level software for laboratory purposes to control FPGA-based LLRF electronic equipment for TESLA. There is presented a universal solution for particular functional devices of the control system with FPGA chips. The paper describes architecture of software layers and programming solutions of hardware communication based on the proprietary Internal Interface (II) technology. Such a solution was used for the Superconducting Cavity Controller and Simulator (SIMCON) for TESLA experiment (Test Facility) in DESY. The examples of the build and tested software blocks were given in this paper. This documentation is a unity with TESLA Reports published in 2004 by the Elhep and describing the SIMCON hardware, ver.2.0. The paper was written in a form of a User's Manual.

The paper describes the concept and realization of the DOOCS control software for FPGA-based TESLA cavity controller and simulator (SIMCON). It bases on universal software components, created for laboratory purposes and used in MATLAB based control environment. These modules have been recently adapted to the DOOCS environment to ensure a unified software to hardware communication model. The presented solution can be also used as a general platform for control algorithms development. The proposed interfaces between MATLAB and DOOCS modules allow to check the developed algorithm in the operation environment before implementation in the FPGA. As the examples two systems have been presented.

The paper describes the concept and realization of the DOOCS control software for FPGA-based TESLA cavity controller and simulator (SIMCON). It bases on universal software components, created for laboratory purposes and used in MATLAB based control environment. These modules have been recently adapted to the DOOCS environment to ensure a unified software to hardware communication model. The presented solution can be also used as a general platform for control algorithms development. The proposed interfaces between MATLAB and DOOCS modules allow to check the developed algorithm in the operation environment before implementation in the FPGA. As the examples two systems have been presented.

The note describes integrated system of hardware controller and simulator of the resonant superconducting, narrowband niobium cavity, originally considered for the TTF and TESLA in DESY, Hamburg (now predicted for the W V and X-Ray FEL). The controller bases on a programmable circuit Xilinx VirtexII V3000 embedded on a PCB XtremeDSP Development Kit by Nallatech. The FPGA circuit configuration was done in the VHDL language. The internal hardware multiplication components, present in Virtex II chips, were used, to improve the floating point calculation efficiency. The implementation was achieved of a device working in the real time, according to the demands of the LLRF control system for the TESLA Test Facility. The device under consideration will be referred to as superconducting cavity (SCCav) SIMCON throughout this work. This document is intended to be used by end users and operators. It describes step by step how to install SIMCON in specific configuration, how and what software to copy to computer. There is described set of basic Matlab functions for developers of control algorithms. This paper also contains brief description how to use Matlab function of one algorithm with its graphic user panels. This TESLA Report is in close relations with the following TESLA Reports published previously: 2005-05, 2005-02, 2004-10. Together, these Reports make a full SIMCON manual.

Radiation produced during the operation of high energy linear accelerators can pose a real danger to electronic devices. The electronics of X-Ray Free Electron Laser (X-FEL) accelerator will be placed in the main tunnel, therefore the system will be subjected to gamma bremsstrahlung radiation and neutrons. Digital Signal Processors (DSPs) and high-density Field Programmable Gate Array (FPGA) devices are used to design the control system of the X-FEL accelerator. Influence of gamma on electronic systems can be decreased by implementation of suitable shielding. Despite the plurality of available methods protecting digital devices against neutrons influence, designing complex systems dedicated to operate in radiation environments is still a challenge. The mechanisms improving immunity of the digital systems can be achieved as an implementation of hardware redundancy or software algorithms modifications. In both cases additional resources are necessary. This paper highlights a DSP-based development environment, based on Texas Instruments TMS320C67 13 digital signal processor, dedicated to test software in radioactive environment. The master-board of the system is connected to the slave controller through EIA 485 differential interface, which assures reliable transmission for a long distance even in EMI polluted area. The developed programs can be downloaded through the interface and stored in a Flash memory. Methods allowing improving the immunity to neutrons generated events, particularly Single Event Upsets (SEUs), were developed using triple redundancy, Hamming codes and doubled multipliers. Different experiments were carried out in Linac II accelerator to evaluate the designed programs and examine the whole system.

In the paper modelling of FIR filters by means of Verilog and SystemVerilog is presented. Hardware/software co-design approach for such systems is applied in the presented design. As a final technology for a FIR filters system implementation, a FPSLIC device is considered. Filters system demonstrates example methods of communication between FPGA and AVR microcontroller in a FPSLIC structure, i.e. the communication through SRAM memory, addressing lines, data bus, interrupts. It also demonstrates how to serve peripheral elements in FPSLIC device by means of DPI interface. FIR filters model contains also interface which implements a FPSLIC cache logic and gives opportunity to a dynamical reconfiguration of FPGA in a FPSLIC structure.

"Pi of the Sky" is a detector designed for search for optical flashes of cosmic origin in the sky. Its primary goal is to look for optical afterglows associated with the gamma ray bursts (GRB) but it is capable to detect also other optical transients of extragalactic origin. The apparatus consists of two arrays of 16 cameras each, which allow for simultaneous observation of large part of the sky. Thanks to on-line data analysis in real time, it has self-triggering capability and can react to external triggers with negative time delay. The prototype with two cameras has been installed at Las Campanas (Chile) and is operational from July 2004. General idea of experiment, the apparatus and its performance will be presented.

Modem research trends require observation of fainter and fainter astronomical objects on large areas of the sky. This implies usage of systems with high temporal and optical resolution with computer based data acquisition and processing. Therefore Charge Coupled Devices became so popular. They offer quick picture conversion with much better quality than film based technologies. This work is theoretical and practical study of the CCD based picture acquisition system. The system was optimized for "Pi of The Sky" project. But it can be adapted to another professional astronomical researches. The work includes issue of picture conversion, signal acquisition, data transfer and mechanical construction of the device.

The CCD Toolkit (1) is a software tool for testing CCD cameras which allows to measure important characteristics of a camera like readout noise, total gain, dark current, 'hot' pixels, useful area, etc. The application makes a statistical analysis of images saved in files with FITS format, commonly used in astronomy. A graphical interface is based on the ROOT package, which offers high functionality and flexibility. The program was developed in a way to ensure future compatibility with different operating systems: Windows and Linux. The CCD Toolkit was created for the "Pie of the Sky" project collaboration (2).

Effective search for gamma ray bursts optical counterparts and other fast astrophysical phenomena requires robotic telescopes. Such telescopes have to be able to realise programmed survey schedule and to react to various kind of alerts. Robotic telescope used in the prototype phase of the "Pi of the Sky" project is described. Design of the full size detector is briefly presented.

The "Pi of the Sky" project is an attempt to create fully autonomous system for detection and analysis of optical flashes in the sky at the time scale of seconds, which are connected with gamma ray burst (GRB). This paper presents briefly the "Pi of the Sky" observing strategy. Test toolkits for schedule scripts and sky scans is described. Application of web services technology for data analysis in the experiment is discussed.

This paper describes PiMan, a CORBA based system manager of the "Pi of the Sky" experiment. The "Pi of the Sky" experiment, located at Las Campanas Observatory in Chile searches for rapidly changing optical objects such as Gamma Ray Bursts (GRB). The system is composed of two CCD cameras located on paralactic mount and operated by a PC, equipped with the dedicated software. The software, divided into modules that correspond to hardware or logical components, controls all aspects of data collection and on-line data analysis. The PiMan assures communication between modules, coordinates their behavior and gives possibility to operate the system automatically and to control it remotely over low bandwidth and unstable link.

The main aim of the "π of the Sky" project is all night monitoring of a large sky area in search for GRB optical counterparts. Contrary to the most of existing experiments, "π of the Sky" does not rely on satellite GRB triggers only, but independently detects optical flashes in the sky and later seeks an association with a satellite alert. This approach requires an efficient self-triggering system, capable of reducing the rate of flash candidates to an amount suitable for a human-eye analysis. This paper covers main aspects of our flash recognition algorithms, briefly describing main false event types that are encountered as well as cuts designed to eliminate them. Physical results based on the data gathered by the "π of the Sky" apparatus prototype during it's first year of operation are presented.

The detector "Pi of the Sky" searches for optical flashes in the sky. Its main goal is to look for optical afterglows associated with gamma ray bursts (GRB), but it also has a capability to detect other phenomena like variable stars. Collected data passes through a specially designed software pipeline. At last. a collection of stars' light curves is obtained and put into a database. At this level it is possible to study stars and analyse their variability. Example results are presented.

The paper presents a project of ground module of localization subsystem of small space capsule, after its landing on the Earth. The system consists of two parts: space transmitter in the capsule, that uses GPS receiver to determine capsule position and transmits it using 433 MHz band, and the ground receiver that receives transmitted signal and display position of the capsule.

The paper gives the summary of the Polish technical activities in space which have been done for the last 35 years. The long way of Polish space instrumentation is presented - from the simple INTERKOSMOS rocket experiments in the 80's to the current participation in the most important ESA missions. About twenty different experiments are described. The presentation starts with the early ionospheric analyzers and Star-tracker TELEGWIAZDA. A few instruments delivered to different Soviet missions (PHOBOS and PRIRODAiMIR among the others) are presented. The example of Planetary Fourier Spectrometer shows how the experience collected in early Soviet and then Russian missions was used by Polish engineers in the later ESA projects. The last decade characterizes of deep collaboration with ESA. Poland participates in the most spectacular ESA missions: INTEGRAL, MARS EXPRESS, ROSETTA, CASSINI, VENUS EXPRESS and HERSCHEL. The technical activities concentrated and still concentrate mostly in Space Research Center of Polish Academy of Sciences (SRC PAS) where the significant number of instruments have been manufactured. This paper also notices some activities done in other Polish institutions (Aviation Institute, PZL Mielec, Warsaw University of Technology) and present participation of a few students groups from Universities of Technology in Warsaw and Wroclaw in ESA educational projects.

The Local Oscillator Subsystem is a part of the HIFI (Heterodyne Instrument for Far Infrared) project, an infrared heterodyne instrument for astronomical observations on the ESA satellite HERSCHEL. The Local Oscillator Subsystem (LO), provides the signals (480 to 1910 GHz) to the fourteen HIFI input mixers. The subsystem consists of three assemblies: the synthesizer unit (LSU assembly) generates the reference signals in K/Ka Bands, the signals are then distributed to 14 sets of amplifiers and multipliers (LOU assembly. The Local Oscillator Control Unit (LCU assembly) provides the main interface between LO and HIFI/Herschel power and telemetry systems. The unit supplies LO, decodes the HIFI macro-commands, programs and monitors the LSU/LOU parameters and finally controls the operation of the whole LO. This paper presents the general overview of the LO Subsystem and LCU unit. The authors focus on the reliability aspects of the LCU. The methods of biasing, in a "safe" way, of the sensitive microwave components (hardware realization and software procedures) are described in more detailed form.

Students from Warsaw University of Technology undertook building student pico satellite. This article is about CubeSat which is the valid standard of student picosats, practical reason and theoretical base for our experiment. This article contains also mission plan.

Modem Satellites are built by international teams with all the components being created in different parts of the world. Common communication protocols are established by the designers to ensure the compatibility of all the components. Despite of all the detailed arrangements differences may arise that can lead to communication errors. To ensure proper communication between all the satellite's components tests have to be carried out. The methods used nowadays are expensive as the simulators and laboratory models need to be built. The article will describe the ways used to test satellites on the example of the Integral Satellite. It will also present an Author's project of a virtual bus that allows testing of the satellite's apparatus and software during the construction stage of the prototype. Its main advantage is the fact of using the Internet as a way of communication to test the components when they are in there parent laboratories all over the world. VirtualCAN bus is one of the suggestions for other teams building the students' satellite named ESEO within the European Space Agency project (ESA SSETI ESEO).

Tectonic plate motion theory came into being in 1960s. It says what happens on Earth's crust and mantle and why tectonic plates move. There are few geophysical and geodetic techniques to measure plates' shifts. Some of them based on artificial satellites techniques. This presentation shows results received by two techniques: GPS (global positioning system) and SLR (satellite laser ranging).

From many years, satellite obtaining remote sensing data are used for monitoring and research a surface of Earth. Since 1972 when ERTS-1 satellite (Landsat 1) has started a service on orbit, multispectral satellite data has been available for scientists and general public. With typical spatial resolution of 5 - 25 meters we can use this data to analyze a natural and anthropogenic changes on our planet in small and medium scale. Initial data from early 70's have geometric resolution about 70 meters (MSS scanner) which is insufficient for many analyses. After 1995 we can easily obtain a declassified high-resolution military surveillance satellite imagery from CORONA satellites. Data collected from period 1961-1980 in analog form (photographic film) have typically spatial resolution in range 1 - 10 meters, but in wide, panchromatic channel. This article proposes a simple method for retrieving valuable information from series of panchromatic imagery collected over the same area in different seasons. This method utilizes a different properties of land cover types, specially from different vegetation canopies to retrieve a superficial, synthetic spectral channels that can be then analyzed and interpreted. This paper analyzes a method, verifies a results and proposes an interpretation methodology to use with multitemporal CORONA imagery. Concluding, we can obtain a valuable high resolution historical data in multichannel form covering 1972-1980 period. This method can be used for long-time analyses of land cover and land use changes in big scales (up to 1:10,000).

This paper presents our feasibility study of Interferometric Synthetic Aperture Radar (IFSAR) on Moon orbiter.

In this paper a concept of a cheap, lightweight, low power satellite radar for Moon's surface mapping is presented. This radar is designed to work in two modes: two-dimensional imaging (Synthetic Aperture Radar - SAR) and three-dimensional imaging (Interferometric Synthetic Aperture Radar - IfSAR). The proposed radar system performs the functions both of a radar system and a high data rate communication system. This enables costs and weight reduction which is very important in space applications.

The paper presents a project of localization subsystem of small space capsule, after its landing on the Earth. The system consists of two part: space transmitter in the capsule, that uses GPS receiver to determine capsule position and transmits it using 433 MHz band, and the ground receiver that receives transmitted signal and display position of the capsule. A completely practical qualification model of the system transmitter that fulfils all space requirements has been designed and realized.

The equipment for measuring amplitude and phase noise spectrum of signals in frequency range from 25,95 to 37,5 GHz are described. This equipment allows making measurement with high sensitivity at low input power. The sensitivity of amplitude noise spectrum measurement is minus 152 dB/Hz and sensitivity of phase noise spectrum measurement is minus 111 dB/Hz. Experimental results are presented.

The mathematical modeling of thin wall waveguide heating process allows to determine the law of temperature field distribution on their surface. The new physical models of sensors on the absorbing wall principle in the coaxial transmission line were proposed and dissipative losses dependence on frequency in one, two and three layer absorbing wall was analyzed. Methods of calculation and designing of the both quasipoint and extended sensors, located on the narrow and wide waveguide walls were proposed: minimization of effective reflection coefficient of sensors in a wide frequency range was reached. The multiprobe microwave multimeter (MMM) is designed for automated powerful transmission line checking.

The configuration of a compact proving ground designed to measure electric characteristics of antennas with apertures up to 1000 mm and, also, to calibrate the antenna systems of radiometer has been considered. Proving ground consists on non-echoic chamber with a collimator antenna of 2000 mm in diameter and the set of exciters for each frequency band. The antenna to be tested is located in the near field of the collimator antenna. Almost plane waves are realized in the position of the antenna to be tested. The accuracy of fabrication of a collimator antenna surface enables to use it over wide frequency range up to 150 GHz. One proposes measurement methods of the following characteristics of the antenna system of a radiometer - antenna beam width, reflection coefficient, antenna efficiency, frequency and polarization decoupling between radiometer channels, losses and SWR in each frequency channel and other parameters of an antenna subsystem and radiometer calibration subsystem.

The article represents the results of creating and testing in the Special Research Bureau MPEI (OKB MEI) of a space-based multifrequency scanning radiometer for Earth remote sensing. A description of engineering solutions of the radiometer's construction is given and the basic parameters and characteristics obtained as a result of preproduction testing are cited.

The field of a wave passed through an infinite dielectric plate with relative dielectric permeability and conductivity turbulently perturbed have been considered. The solution have been obtained by the method of secondary sources. The signal-to-noise ratio in power in a wave passed through the medium with turbulent parameters have been found. The results of numerical calculations have been presented.

The authors consider the main components of the error of measurement of the radio-brightness temperature of the Earth, including the background radiation of the Sun, and give the example of calculation for different reception frequencies.

The calculation technique of on-board antennas for space vehicles possessing temperature stability characteristics have been presented.

The authors give the results of the designing of the antenna sub-system of the multi-channel microwave scanning radiometer designed for measurement of the temperature patterns of the Earth's surface and installed on a low-orbit satellite. The antenna of the multi-range radiometer is designed on the basis of the offset parabolic reflector. The exciter is the multi-range wide-band horn excited by the side waveguides with the findamental wave H₁₁ (see fig.1). The horn is oriented at 45° to the focal axis of the paraboloid so that to form the conical scanning sector, the generating line of which constitutes a 45° angle with the satellite axis (see Fig.2), as the reflector rotates around the sighting line, which connects the phase centre of the horn with the centre of the offset reflector.

Passive Coherent Location (PCL) is going to be important and perspective system of passive location of non cooperative and stealth targets. It works with the sources of irradiation of opportunity. PCL is intended to be a part of mobile Air Command and Control System (ACCS) as a Deployable ACCS Component (DAC). The company ERA works on PCL system parameters verification program by complete PCL simulator development since the year 2003. The Czech DoD takes financial participation on this program. The moving targets scenario, the RCS calculation by method of moment, ground clutter scattering and signal processing method (the bottle neck of the PCL) are available up to now in simulator tool. The digital signal (DSP) processing algorithms are performed both on simulated data and on real data measured at NATO C3 Agency in their Haag experiment. The Institute of Information Theory and Automation of the Academy of Sciences of the Czech Republic takes part on the implementation of the DSP algorithms in FPGA. The paper describes the simulator and signal processing structure and results both on simulated and measured data.

One of key problem in passive coherent location (PCL) is effective and accurate computation of the cross ambiguity function (CAF). This function is related to the direct signal and signals reflected from localized targets. PCL systems exploit high-power commercial transmitters of opportunity (FM, TV, etc.) to take advantage of lower frequencies, multistatic geometries and covert deployment. The transmitter does not have to cooperate with the receiver. The CAF represent power spectral density distribution of the cross-correlation between direct and reflected signals. It depends on mutual time delay and frequency shift of the input signals and is considerate as primary information for detection, localization and identification of the tracked targets. Regarding above mentioned reasons has to be important develop optimal (numerically effective and sufficiently accurate) implementation of the HW architecture based on FPGA for CAF computation, which will be suitable for future real-time PCL systems. As a first result which originates on the ongoing mutual cooperation between ERA a.s. and UTIA is design of the PC accelerator card for CAF computation based on Xilinx FPGA processor. The presented contribution gives overall information about used algorithms, FPGA accelerator card design and achieved performance. The future possibilities of the additional enhancements are discussed.

Random signals with finite energy in Hilbert spaces are considered. A new probability model of nonstationary random signals and their realizations in the form of two-parametric representation is given. Depending on the correlation function components distribution of the signals two-parametric representation in parametric space, four classes of random signals with finite energy are distinguished.

In this paper the adaptive algorithms for radar signals processing are developed and applied to the detection of turbulent zones in rain. Efficiency of the algorithms is analyzed by statistical modeling. Simulation of weather radar signals and testing of the processing algorithms are performed for comparative analysis of the developed algorithms and known pulse-pair algorithm. The results demonstrate a significant superiority of adaptive algorithms in comparison with the known one. The main emphasis is done to the two-sample algorithm. Algorithms are tested by using the data of Doppler-polarimetric remote sensing of rain. Two-sample algorithm is checked by using radar measurements. Experimental check confirms high efficiency of the two-sample adaptive algorithm. It is recommended for practical use in weather radars.

This paper presents experimental results of a high-power transceiver. Various measured parameters e.g. output power, gain, have been measured and the results are presented. Modular construction of the transceiver allows us to modify the unit to obtain desired output power. The temperature and output power sensors have been implemented and the visualization software has been created. For the purpose of control and monitoring a microcontroller unit is used.

The paper presents basic overview of processing techniques used in radars working with nonuniform sampling of echo signals. In the pulsed or periodically modulated wave radars the sampling of the return signal is inherently connected with the pulse (or modulation) repetition period. Thus, if the period is time-varying, the sampling moments of Doppler echo signal are nonuniformly spaced. The nonuniform sampling enables the use of special processing that makes it possible, under certain conditions, to deduce some signal properties in the frequency range above Nyquist limit.

Polynomial Wigner Ville distribution (PWVD) is considered as a tool for recognition of signals with an unknown frequency modulation law. This time-frequency distribution (TF) with multi-linear kernel is an optimal form for signals with a polynomial frequency modulation law. Instantaneous frequency (IF) is the important property of non-stationary signals, i.e. signals whose spectral contents vary with time. Then the recognition of unknown signals can be formulated as the problem of estimation of its instantaneous frequency. The studies of estimation of IF for noiseless signals can be found in literature. The noise embedded in a signal has large influence on time-frequency distribution and can change the true value of the IF. Time-frequency distribution strongly depends on the kind of noise. In this paper signals embedded in additive gaussian and impulse noise have been considered. Estimation of the instantaneous fiequency in impulsive noise background is different than in gaussian noise and requires robust forms of time-frequency distributions. In this paper the application of the robust form of the Wigner-Ville distribution (WVD_r) and the robust form of the polynomial Wigner-Ville distribution (PWVD_r) for IF estimation is presented. Maxima of these distributions are assumed as the estimates of true values of IF. The theoretical background of WVD_r and PWVD_r distributions is introduced and several numerical experiments of IF estimation are presented.

In article a particle filter, a relatively new approach to filtering in non-linear, non-Gaussian problems, is being presented. Authors have conducted an experiment, in which a target moving with a constant speed is being observed through its bearing and a filter is used to extrapolate the target's expected bearing in the next discrete time moment. The filter performance is evaluated and compared to results from more traditional filter, in both accuracy and calculation time aspect.

The article presents the results of research on the effect of selecting various parameters of a neural filter based on GRNN network, applied for the state vector estimation of a maneuvering target in ARPA devices. There was tested the effect of teaching sequence length, the application of successive estimating stages and the changes of smoothing factor on the state vector of the maneuvering target. A statistical response of filters was found by means of the Monte Carlo simulation method.

In this paper the passive methods of detection and measuring distance to a source of lightning discharge are considered. A new method is presented and correspondent algorithms of signal processing are developed for measuring the distance between the aircraft and a source of lightning. The function of devices that can be designed on the basis of the method consists in timely detection of a lightning threat in order to provide the pilot with necessary information to avoid dangerous zones during the flight. This is especially important under the condition of new CNSiATM concept and 'free flight' policy when a pilot has much more freedom for decision making. The method uses the orthogonal (on polarization) components of electromagnetic field generated by lightning as measurable values. Limitations of the method are analyzed and comparison with other methods is done. Advantages and peculiarities of new method are shown. The method can be implemented as a device for small aircraft instead of weather radar. Other using of proposed method is application together with airborne weather radar on the basis of data fusion and displaying resulting information.

A method is described for generating random Noncentral Chi-square Gamma (NCSG) vectors with specified parameters. Such vectors may represent samples of clutter signal. The presented method makes use of the suitable transformation of the random Gaussian vectors. Computer simulations aspects of the method are also discussed.

The paper presents limitations of space borne synthetic aperture radars, caused by range and Doppler velocity ambiguities, and the concept of usage of the noise radar technology for creation of high-resolution space SAR images. The noise SAR is free from limitation caused by the periodicity of pulse waveform ambiguity function, and therefore this technology can be used in the future space missions. The basic concept of noise SAR image formation is also presented. The image formation algorithm has been verified using the simulated data produced by Raw Radar Data Simulator.

Synthetic Aperture Radar systems are usually based on the type of radar that utilizes Linear Frequency Modulation for SNR increase. Currently, interest in alternate radar types is growing. In this paper Noise Waveform (NW) as applied to the Synthetic Aperture Radar technology was evaluated. Expected properties of the KW were assessed through conventional image quality parameters and compared with those for the Linear Frequency Modulation based SAR.

The article presents multilook processing in Unfocused Synthetic Aperture Radar (Unfocused SAR). Multilook processing reduces so called speckle noise, inherent to SAR imaging, by averaging several independently obtained images. Typically, multilook is used in Focused SAR and leads to reduction of resolution. Proposed concept of multilook in Unfocused SAR reduces the variance of the speckle without deterioration of the resolution.

Quality of Synthetic Aperture Radar (SAR) images is very sensitive for both pulse signal spectrum purity and stability of the radar platform flight path. In this paper detailed influence of this factors on SAR images quality is analyzed. Analysis is based mainly on computer simulations. This kind of analysis is very important because not all SAR image degradation factors can be compensated using digital signal processing algorithms.

This paper presents comparison results of non-coherent autofocus methods. Key to comparison was achieved resolution and computational complexity. The goal of this work is investigating efficient methods of improving resolution that could be implemented in real time SAR systems in the future.

Influence of antenna motion distortions for the ground based D-InSAR is considered. Analysis of the relations between the phase errors and antenna positioning precision for D-InSAR antenna system is presented. The analytical relation is obtained for the phase errors of D-InSAR with linear aperture and was used in case of various antenna trajectory distortions: shifts along any direction, rotations in azimuth and elevation planes and random shifts. Theoretical results are validated via computer modeling of the noise SAR system. The results obtained via modeling and analytical relations are in a good agreement and may be used for ground based SAR antennas design and interpretations of the generated SAR interferograms.

This paper analyses impact of using averaging filtering on quality of SAR images. These are commonly corrupted by multiplicative complex correlated noise (speckle) and by additive white Gaussian noise. Methods presented in this paper: multilook algorithm and averaging filters are examined in the context of additive white Gaussian noise reduction and computational demands. In order to obtain high cross-range resolution of SAR images Map-Drift Autofocus algorithm is also employed.

In this article we would llke to present our results of Interferometric Synthetic Aperture Radar Processing. This technique is extension of classical SAR and allows us to obtain high resolution digital elevation model of observed scene.

The publication presents problems emerging from the area of overlapping of two advanced radar techniques: Airborne Moving Target Indication (AMTI) and Synthetic Aperture Radar (SAR). The first technique applied to airborne radar systems, especially in fighters and Airborne Early Warning systems does not require high resolution abilities from radar systems, but its high computational requirements result from the necessity of fast and usually adaptive matching of system characteristics to rapidly changing disturbances. The second technique, based on the quasi stationarity of the electromagnetic field in the observed space, allows to obtain a high resolution radar image only for non-moving objects. The computational complexity of SAR algorithms is connected with large amount of data collected during the observation period. The attempt of application of SAR system to detect and exactly localize moving targets leads to certain distortions and deformations in radar image. This paper presents impact of the movement of targets on SAR image and possible ways of improvement of its quality and determining of movement parameters.

Paper concerns a method of extracting cross sections of objects placed on revolving platform from a matrix constituted by signal received coherently for different angles. There are utilized short pulses, with broad frequency bandwidth. Calculations of an image are based on phase shift between received pulses. Paper includes preliminary results of experiments.

There is an increasing demand in replacing SnPb solders with Pb-free solders in the electronic industry due to health and environmental concern. The European Union passed a law to ban the use of lead in electronics on February 13, 2003. The ban goes into effect on July 2006. The aim of the paper is to overview the necessary changes in materials and technologies for "green" electronics products. The materials and assembly technology changes on first-level package as well as on second-level package will be presented. Detailed analyse of some Pb-free solders as well as Pb-free component and PCBs finishes properties will be done. Some experimental data comparing Pb-free and SnPb solder joint properties are summarized. Finally the paper gives perspectives of transitions to a totally Pb-free manufacturing.

The electronic industry is engaged in developing Pb-free technologies for more than ten years. However till now not all properties of new solders are described. The aim of the paper is to present some electrical properties of new series of Pb-free solders (eutectic SnAg, near eutectic SnAgCu with and without Bi) in low temperature ranges 10 K to 273K. The following parameters were analyzed: electrical resistivity, temperature coefficient of resistance and thermoelectric power. The electrical resistivity at temperatures above 50 K is a monotonically rising function of temperature for Pb-free solders studied. The electrical resistivity of the Bi containing alloys is higher as compared to the remaining ones. The thermoelectric power values at room temperature are about -8 μV/K to -6 μV/K for Pb-free solders studied, being higher as compared to typical values -3 μVK of SnPb solder. The relatively low absolute values as well as the smooth and weak temperature variation of electrical resistivity in lead free solders enable the possible low temperature application. The moderate values of thermoelectric power around and above the room temperature show that when applying the solders studied the temperature should be kept as uniform as possible, in order to avoid spurious or noise voltages.

Extremely quick progress in miniaturization and functionality of electronic components more and more influences design and manufacture of Printed Circuit Boards (PCBs). Especially it concerns miniaturization and increasing of interconnection densities. The quality and reliability of manufactured interconnects depends on metallization technique. The aim of the paper is to describe the different plating techniques of High Density Interconnections (HDI) in PCBs.

Intermetallic compounds (IMC) can not be disregard during consideration referred to the reliability of solder joints. In connection with removing lead from consumer electronics, the reliability of the Pb-free solders seems to be a crucial and worth of attention problem. Occurance of the IMC may significantly cut down the up time of interconnection causing that solder joint cracks easily. The influence of the IMC on the reliability of solder joints depends on properties of the IMC and reactions between the IMC and both boundary layers and solder mass. The IMC is not the only factor which has an effect on the reliability of solder joints. The others are for example soldering conditions, composition of alloys and layers, appearance of specific multilayers and correlations between them. In this study considerations are focused only on the IMC problems. Interfacial reactions, specific ripening of IMC and a long range interactions will be presented and explained.

Electronic products in a market since the 1st of July 2006 will have to be devoid several dangerous substances, for example lead. The introduction of lead-free technology require searching new solder alloys and fluxes as well as necessity of the examine properties these materials. The Wetting Balance Method is method which makes possible the checking of wetting parameters of new lead-free materials as well as examining of mutual their co-operation in lead- free technology. The advantages and possibility of the above mentioned method will be shown in the article. The evaluation of new lead-free materials for assembly processes of electronics packages will be used as example of application this method in research process.

TE₀₁₁ mode cavity method is presented for the surface resistance and conductivity measurements of thin metal films deposited on dielectric substrates. Rigorous solutions of multilateral metal-dielectric resonator structure are given that allow to determine surface resistance and conductivity from measured Q-factors and resonant frequencies of the structure. Measurements of several thin films have been performed at frequencies 9 GHz and 17 GHz

Simple method of Keithley 2001 multimeter resistance measurement range extension towards low resistance is presented. Extension was accomplished by test current increase. The test current was increased by one hundred times and resistance measurement resolution was increased from 1 μΩ to 10 nΩ. But this is not hardware limit of this method. Real limit of test current increase and resistance measurement range extension is heating of the object under measurement. The method is cost effective. It needs only a stable current source and a simple switch.

This paper describes the design parameters and construction of current sensor based on printed circuit board (PCB) coil. This sensor is contactless and can be used in remote conductors at high potentials. This sensor doesn't have iron core (unlike current transformer) so there is no non-linearity over a very wide measurement range. Unlike a shunt resistor, this sensor provides galvanic isolation and produces no heating.

A method of analysing the distribution of temperature fields in electrolytic cell is described. The finite volume method, a kind of approximated numerical method, is used to solve a complex and dual-field problem, where the mass transport of the circulating electrolyte is coupled with effects of transport of heat energy. A specific correct distribution of the temperature around the cathode plays a significant role in the electroplating process. This problem is discussed in the paper. Some useful remarks concerning of the heat sources and thermal field in the electrolyte are presented. As an example of the use of these methods, a test model is analysed. The comparative results are obtained for the reduced two-dimensional models.

Heavy metal oxide lasses doped by Dy³⁺ ions for optical fibres with the numerical aperture 0,4-0,9 fabrication is presented. Heavy metal oxide glasses in the system Pb0-Ga₂0₃-Bi₂0₃-Cd0 doped by 1500 ppm Dy³⁺ ions were used. The method of their preparation and physical properties as well the results of luminescence investigations of Dy³⁺ ions embedded in glass hosts are reported. Double-crucible drawing technique was applied to obtain optical fibre doped by Dy³⁺ ions. Core and cladding glasses have been obtained by modification the base glass with small amounts of cadmium and gallium. In such a way these glasses possessed the same technological parameters which can be controlled in a wide range.

Heavy metal oxide glasses in the system TeO₂-PbO-WO₃ doped by selected rare earth ions have been presented. The method of their preparation and physical properties were determined. Infrared luminescence of Er³⁺ and Tm³⁺ ions embedded in TeO₂-PbO-WO₃ glass hosts is reported for room and helium liquid temperatures. The substantial influence of energy transfer processes between the glass host and Er³⁺ and Tm³⁺ doped ions is shown experimentally through the dependences of photoluminescence on light polarization and excitation wavelength. The presented spectra of the rare earth doped glasses indicate on a possibility of their excitation by the Nd-YAG laser with wavelength about 1,06 μm. Because of their properties this kind of glasses can be used for construction of optoelectronic devices.

Microporous glasses from the Na₂O-B₂O₃-SiO₂ system can be obtained by appropriate thermal and chemical treatment. During the thermal treatment the separation of the borate phase from the silicon skeleton has been occurred. The borates are in the form small drops joined to each other. In the course of chemical treatment the borates become leached in water, water solutions of acids or basis and the glass becomes porous. Microporous glasses may find application in many branches of science and engineering. The applications depend on the internal arrangement, size and shape of pores. These parameters may be in a wide range modified by a change of the chemical composition. The received porous glass was used as an element in optical fibre NO₂ sensor. The specific coloration reaction between organic reagents and NO₂ in the pores was occurred. It is possible to detection of 10-50 ppm NO₂ level.

The following paper presents the construction and operation principles as well as measurement results for the manufactured stress sensors. The elaborated stress sensor was manufactured using double-core optical fibres and employs the dependence of variations in the coupling index between the fibre cores against the applied stress.

The paper presents the possibilities of utilization plastic optical fibers, which cooperate with commonly available transmitters and optical receivers TOSLINK (developed by TOSHIBA), in industrial electronics systems. The optical transmission links based on plastic optical fibers allow to send digital signals in industrial environment, assuring galvanized separation. The proposed solutions were implemented and successfully tested in real-time digital systems.

Hollow waveguide is attractive media for transmission infrared radiation. Reflective gold layer can be alternative for other coating materials in hollow waveguides. This paper presents the ability to fabricate hollow waveguide with gold layer inside glass tube and analysis of bending losses in hollow waveguides. It also presents theoretical analysis of attenuation coefficient for waveguide with gold layer inside glass tube.

This work presents the idea of the conversion of the optoelectronic system into the functional electric model on the example of fiber amplifier. The functional model is formulated in a long line of lumped constants form. It is dedicated for electrical simulators like SPICE (Simulation Program for Integrated Circuit Emphasis). It can be widely used in design and analysis of fiber transmission lines, whose optical fiber amplifier is one of the most important parts. This model together with previous showed analysis enables qualification time life of ions in excited state in working amplifier.

In this paper we analyze the threshold violet and ultra-violet laser operation in Nd³⁺ doped ZBLAN fibers, using relatively fast and accurate method, based on measured spectroscopic parameters like fluorescence lifetimes and emissiod/absorption cross-sections spectra. Our approach, which is based on energy theorem and threshold field approximation, extends the model presented in [1] by taking into account the longitudinal and transverse field distribution of the fiber laser mode. Specifically, in this work we compare the efficiency of two possible laser pumping schemes: direct and two-photon excitation. The problem of laser resonator optimization is discussed by providing the analytical formulas for small signal gain in active fiber medium as a function of structure parameters i.e. the cavity geometry, distributed losses of the active medium, output power level and the mirror reflectivity. As the result of the carried-out optimizations we can determine the conditions for obtaining short-wavelength lasing in Nd:ZBLAN fiber laser with minimal threshold and maximal output power level.

Classical polymer optical fibers are made with chemicals. The core has the large diameter, and the clad is a thin layer of modified polymer. The clad radiation can propagate quite well in specialist polymer fibers as double clad. It can also be generated in specific situation in classical polymer fibers. This work presents the idea of clad radiation rating in classical polymer fibers. Clad radiation phenomenon functional model has been proposed. The experiment data has been used for specification of it parameter's values. The experiment examples, which demonstrate model correctness, are shown.

In this paper a project of a simple optical fibre ultraviolet sensor was presented. As the main part of the sensor, the active layer containing an organic dye able to absorb ultraviolet radiation and afterwards emit radiation in a visible range underwent the detailed investigation. The Atomic Force Microscopy (AFM) images of the gel active layers clearly proved a relation between the surface structure, time of sol's hydrolysis and the compositions of the sols which differed with the molar ratio of three alkoxysilanes (TEOS- tetraethoxysilane, MTES- methyltriethoxysilane and PhTES- phenyltriethoxysilane). The experiment was being carried out during 42 days with the measurements every 7th day. Additionaly, a dependence between the structure of the examined surface (which means also a dependence of both remaining factors mentioned above) and emission's intensity of the sensor while excitated with a banknote-control UV standard lamp has been noticed. The obtained results give an obvious prove the optical properties of UV optical fibres' sensor in which a gel active layer is applied depend on many different factors, which adequately matched may result in a big sensitivity and efficiency of such a sensor.

Construction of strain sensor for application in safety systems has been presented. The device consists of sensor's head and source and detector units. The head is made of polymer fiber bends. Designed sensor could be mounted in monitoring place (e.g. under a floor) and controlled by PC unit or could be used as a portable device for a valuable object protection.

The goal is to model the behaviour of an apodized fibre Bragg grating (FBG) under impulsive strain of rectangular shape. The transfer matrix method has been applied in this analysis. The changes induced in a spectrum of FBG are calculated based on the piecewise-uniform period assumption for chirped gratings. The result demonstrates changing spectrum of a FBG during processing impulsive quantities with different amplitudes.

The results of numerical analysis of the influence of the initial pulse shape on the propagation of the pulses in a birefringent nonlinear single mode fiber for the case of unequal excitation of the polarization components are presented in the paper. The following shapes of the initial pulse were investigated: hyperbolic secant, Gaussian, super Gaussian, super Gaussian second order. The analysis was carried out by numerically solving a pair of coupled Nonlinear Schrodinger Equations using the Split Step Fourier Method. The calculations were performed for an optical fiber made of silica glass. The fiber attenuation was not taken into account.

This paper presents investigations of optical-microwave mixing process for PIN photodiode. A nonlinear equivalent circuit of the photodiode and a method of circuit extraction are presented. The model of a most significant PIN photodiode nonlinearity - a nonlinear responsivity is proposed. Obtained results of measurements and simulations are compared and discussed.

On the basis of the previous investigations the new construction of measurement system with strain gage transducer based on double current bridge is presented. The idea of measuring two different parameters at the same time in one circuit-bridge is described. The system allows for measurement of axial and bending forces acting upon the beam.

This work presents a mathematical analysis of the propagation of luminous flux in the curvatures of optical fibres based on the equation of a torus. The influence of the fibre curvature on the value of the luminous flux transmission coefficient was determined. On the basis of this analysis a computer program has been designed enabling to determine the transmission coefficient of the optical fibre. Comparing the data obtained from the computer simulation with the data from experimental verification it may be stated that the program determines the loss factor resulting from the fibre curvature quite well. The error between the actual measurements and the results obtained from the computer simulation ranged from 1,8% to 12,2%. The program may be a useful tool for designing lighting optical fibres used in various types of optical fibre systems.

Analysis of luminous flux transfer trough a conical ring-core light guide is presented. This kind of optical guide is used by the authors to build a measuring device which enables to determine the distribution of luminance in the visual space. The angles of acceptance can be selected at random, thus the solid angle, in which the distribution of luminance is analysed, can practically be divided into a chosen number of zones. In the section perpendicular to its axis, the light guide can have an elliptical shape with different angles of acceptance. In such a way it is possible to adjust the division of the space into zones better and create a parallel with two-eye sight (smaller zones in the vertical section, bigger in the horizontal plane). The conical output surface with great vertical angle considerably improves the process of the transfer of the luminous flux trough a conical ring-core light guide. Replacing a flat outlet surface of the light guide by a conical one makes the transferred luminous flux to some extent more uniform.

We have discussed transmission of the luminous flux through the optical fibre with a flat input surface and a spherical output surface. In this discussion we have considered the basic losses of the luminous flux.: Fresnel reflections, absorption of the core material on the optical path, and imperfections of the internal reflection. The curves of luminous intensity of the solids of light distribution in the optical fibre mating with a halogen bulb have been given as well.

The work presents the analysis of the luminous flux distribution in the transverse section of a fibrous optical fibre, in the function of distance from the fibre input face. The simulation is based on the Monte Carlo method of light calculations carried out with the use of specialist software. The simulation results refer to the distribution of luminance and the fibre efficiency depending on the applied light source.

The recommended by the CIE method of the discomfort glare evaluation demands the knowledge of the luminance distribution in interior, size and location of each glaring area. These quantities can be pointed out of measurements conducted by means of superficial detector. Received map of luminance distribution must be numerically analyzed.

An option for the measuring cameras with lens may be the configuration of pinhole camera. An experiment was conducted. Its goal was an appraisal of this configuration with respect to the application in photometry, especially in luminance distribution measurements. In the paper some results of this experiments are presented.

The paper presents some improvements to the transmission line model of photacoustic Helmholtz cell. The improvements were aimed to obtain much better agreement between theoretical and practical values of Q-factors of the cells, and were based on measurements of number of cells and comparison of measurement results with theoretical frequency responses. The measured cells had dimensions typical for photoacoustic setups.

The paper presents some aspects of digital signal processing of sampled photoacoustic signal. In particular influence of DC drift and noise on photoacoustic signal amplitude detection errors is discussed. Some methods of dealing with these problems are described. Real-time sampling and stroboscope sampling are considered.

The paper describes a truly miniature system for data acquisition and control, dedicated for photoacoustic measurements. Due to intensive use of electronics and digital signal processing most of expensive and/or inconvenient elements of photoacoustic setups, like mechanical chopper or lock-in amplifier, were eliminated. The advantages of the designed device are very low cost, small size, and high functional flexibility. Most of the measurement factors, e.g. analog path gain, light source modulation frequency, number of samples a period, etc. are programmable and can be changed at run-time. Implementation of real-time and stroboscope PAS signal sampling makes possible to acquire high resolution samples while preserving wide input bandwidth. Due to in-circuit programmable components, upgrades of the device are very easy. Small size and low power consumption make the device a very good choice for implementation of portable photoacoustic instruments.

The paper describes experimental results of photoacoustic pulse stimulation of a Helmholtz resonator in which influence of pulse duty factor on the signal amplitude was studied. The signal was measured by means of a dedicated microprocessor system capable of recording the signal shape and frequency response of the cell. Relationship between the light pulse duty factor and signal in the photoacoustic Helmholtz cell at different frequencies is presented.

This paper presents method and performance of the double Helmholtz photoacoustic resonator that can be used to improve excitation of acoustical response of the photoacoustic cell by photoacoustic effect and by electromechanical means. The presented method can be used to evaluate energy efficiency of the cell and the associated electronic circuit, to determine overall sensitivity of the set-up, its signal to noise ratio, etc. Electromechanical means of exciting acoustic field inside double Helmholtz photoacoustic cell is easy to perform and allows to simulate photoacoustic signal response in various experimental set-ups. This method uses acoustical pressure produced by a piezoelectric disc mounted in the cell and driven from an external oscillator circuit. The practical experiments show good adherence of the photoacoustic cell frequency dependent acoustical characteristics, obtained by electromechanical method and by photoacoustic method. Equivalents of acoustical response of the photoacoustic cell by both methods has been shown.

The article describes implementation of Random Repetitive Sampling Oscilloscope based on an FPGA device. The main idea was to achieve high quality instrument at moderate costs. The oscilloscope consists of analogue and digital blocks and most of the digital circuits were implemented in a programmable device, which reduces production costs. Time base and data acquisition circuits are discussed in details. Use of FPGA makes the design more flexible, as changes of the unctionality of the device will not affect hardware. Use of FPGA makes it easy to implement additional functions, e.g. IEEE 488 interface core, if the device is to be use in automatic measurement systems.

The paper presents a low-cost fast ramp circuit for use in sampling oscilloscope. A structure and a principle of operation of the circuit are described. The way of realisation and results of measurements are announced too. Usefulness of the circuit for fast sampling oscilloscopes is estimated.

The paper presents an approach to the design of sampling pulses generator for wideband sampling circuit. Generator is based on Step Recovery Diode (SRD) and slot transmission line (TL). Computer simulation allows for adjusting length of transmission line in the circuit with previously characterized SRD, so as to shape the output pulse in the optimal way.

The paper discusses some problems concerned with instability of time delay in ultra fast sampling circuits, used in digital oscilloscopes of gigahertz bandwidth. Measurement of thermal change of delay time of step recovery diodes are presented. Suggestions how to reduce and/or compensate the effect are included.

This paper presents the precise low current source circuit for use in a time measurement system with a time expansion. The circuit's design and structure are shown, with a special attention brought to the problems during the system construction. The results of essential measurements are also shown. These results confirm the value of presented solution.

The paper concerns the shape distortions observed in transmission lines used for delaying fast pulse signals e.g. in Y - channels of high - speed oscilloscopes. Such delay lines should introduce no distortions at all. Yet not having possibility to avoid the skin-effects, there exists a need of at least estimation of pulse shape changes caused by skin effect for given realisation of the delay line. This paper shows an attempt to such an estimation using well-known simulator from PSPICE family.

In this paper the construction of low-cost mobile robot set up of LEGO bricks is presented. The robot vision software is based on cellular neural network image processing. The robot is able to find out a target - shining light - in the dedicated environment starting from any initial position. The most severe limitation of the robot functionality is its speed.

This paper presents a hardware based approach to accelerating sequential minimal optimization algorithm for training support vector machines. As an example of hardware that the algorithm can be accelerated on programmable graphics processors and processors supporting SIMD extensions have been chosen. Such hardware is becoming more popular in a consumer level PCs with each passing year and therefore solution proposed in this paper can benefit from present hardware that has not been utilized up until now.

Non parametric inference error, the error arising from estimating the regression function based on a labeled set of training examples could be divided into two main contributions: the bias and the variance. Neural network is one of the existing models in non parametric inference whose bias/variance trade off is hidden below the network architecture. In recent years new and powerful tools for neural networks selection were invented to impact the bias variance dilemma and the results in the implemented solution were satisfying [11,12]. We exploited the new measures introduced in these works for implementing a genetic algorithm to train neural networks. This method enables a reliable generalization error estimation for neural model. Estimating the error performance permits to drive correctly the genetic evolution that will lead to a fitting model with the desired characteristics. After a brief description of the estimation technique we used the genetic algorithm implementation for artificial data as a test. Finally the results of the fully automatic algorithm for NN training and model selection applied to investigation of defect structure of semi-insulating materials based on photo-induced transient spectroscopy experiments.

Selection of neural networks for function approximation are well known and widely described in many recent papers. This study extends the understanding of the problem on different areas of optimization. Typically selection of best model reduces to searching for models that best fit to leave-one-out criteria. This work joins leave-one-out criteria with genetic algorithms optimization methods and implements it with respect to Pareto optimum. Algorithm constructed in this study basis on presented methods and was applied in semi-insulating materials approximation problem as well as synthetic data models selection.

Support vector machines with Gaussian kernel are used in classification tasks with linear non-separable data. The Gaussian kernel is parametrized by two values (hyperparameters): C,γ. Hyperparameters selection, also known as model selection, affects the generalization performance of classifier. Retaining high generalization performance is vital to achieving good prediction results on unknown datasets. There is no strict rule for proper model selection. The range of hyperparameters' values is wide, so this is a time consuming task in general. In our approach genetic algorithm is exploited to find optimal hyperparameters values.

Cancer diagnosis is one of the most important clinical applications of gene expression microarray technology. It is not easy to indicate which of genes are directly liable for evolution of the cancer. So, computer methods of analysis of gene expression are wanted. The paper presents some solution to this problem by applying Support Vector Machine (SVM) network. The important stage of this approach includes the generation of the features on the basis of which SVM will recognize all genes for which change of expression is significantly big in the process of tumor evolution. Results of computational experiments will be presented and discussed in this paper.

In the paper the problem of low-jitter clock recovery in the fiber optic transmission is discussed. The basic receiver structure is presented and the the amplitude noise to jitter conversion phenomenon is carefully analysed. The special attention is paid to the low-pass filtering of the received signal. The contradiction between low-BER and low-jitter oriented filtering its pointed out. To verify the theoretical analysis results the hardware experiment and the measurement results are also presented. Some practical conclusions are drawn and among others the use of excess bandwidth of the fiber optic transmission channel is proposed as the basic way of the received signal jitter reduction. In the final part of the paper the new concept of the low-jitter and low-BER fiber optic receiver structure is presented.

The article includes a description and implementation of the adaptive algorithm based on the minimalization of error mean-square aiming at limiting the level of a type of random interference proposed by the author. The proposed rado noise has good noise characteristics. Moreover, the article discusses a problem of suppression of echo interferece coming from telecommunications transmission line. The influence of echo interference on the working of transmission systems has been analyzed and the paper concerns also the future use of methods for limiting the level of echo which are currently functioning in the form of structure in lines and channels of digital transmitting systems.

Modern electronic industry takes many efforts to reduce the power dissipated on single chip and as it was reported, up to 50% of this total power is caused by Clock Distribution Network (CDN). What is more, it is getting worse when speed increases. That is why this matter is investigated and new solutions are under deep research. Optical signaling seems to be very promising here, because of broad bandwidth, noise conditions etc. This paper discusses the Electrical Clock Distribution Networks (ECDN) versus Optical Clock Distribution Networks(OCDN) and contains short summary of some typical, published solutions of the circuits of the optical receivers. It shows the commonly used topologies and technologies of the optical receiver circuits and tries to point out their strong and weak sides.

Intrusion Prevention Systems (IPSs) have become widely recognized as a powerful tool and an important element of IT security safeguards. The essential feature of network IPSs is searching through network packets and matching multiple strings, that are fingerprints of known attacks. String matching is highly resource consuming and also the most significant bottleneck of IPSs. In this article an extension of the classical Karp-Rabin algorithm and its implementation architectures were examined. The result is a software, which generates a source code of a string matching module in hardware description language, that could be easily used to create an Intrusion Prevention System implemented in reconfigurable hardware. The prepared module matches the complete set of Snort IPS signatures achieving throughput of over 2 Gbps on an Altera Stratix I1 evaluation board. The most significant advantage of the proposed architecture is that the update of the patterns database does not require reconfiguration of the circuitry.

The advantages of all-optical network's technics make them one of main elements of the metropolitan area networks. They enable different applications in high quality mulitimedia services and guarantee a constant and reliable access to the Internet. As the growing expansion of the Internet continues in an unpredictable direction, many new solutions are expected. The major challenge is the increasing demand for flexible, transparent and customised bandwidth services for both private and business customers.

Bloom filter is an efficient membership queries algorithm that can be used to increase network performance and security. This article considers usage of such a solution in different areas of network processing like IP Tracebacking, IP Lookup in routers or pattern matching in Intrusion Prevention Systems (IPS). It also contains a description of basic theory of Bloom filters, short overview of systems based on this solution and presents results in resource utilization (memory and logic cells) and throughput obtained in our implementations.

In this paper, an analysis of the construction of symmetrical and asymmetrical passive fiber optic structures is presented, as well as an analysis of the possibilities of using a collision detection method in these structures and the possibilities of transmitting optical signals through structures of this type.

The article presents the reliability assessment of a gravity stormwater collection system. The system components were assumed as having two-state fit/unfit for use characteristics, while the entire system was treated as a multi-state object with many states of partial unfitness. The expected value of the reduced area of the drainage basin connected to the unfit fragments of the system was assumed the basic measure of the system unfitness. The uncertainty of this reliability measure was assessed.

The vacuum sewerage system is characterised by periodicity of operation, resulting from temporal and spatial non-uniformity of sewage flow to the system, along with short work times and long idle times. In those specific conditions, the operating parameters are kept by the vacuum station, which is a decisive factor in the reliability of operation of the sewerage system. As a result of monitoring of a selected pumping station, it was concluded that the majority of work times of the vacuum pumps is located within the interval between, approximately, 0,5 and 1,5 min., while the total work time of a pump was equal to as little as 37 min.

The verification of water quality measurement point locations in the monitoring of a selected Water Distribution System (WDS) was executed using a so called maximal detection method, described in [6] and widely discussed in [5]. As a result of application of this method, different numbers of measuring points were determined, along with different locations of those points in the examined WDS. Thus the water quality monitoring system, long in use in this WDS, was verified. Moreover, the use of the maximal detection method has led to higher efficiency of water quality monitoring. The resulting probability of water pollution detection in the water supply network was twice as high as for the existing monitoring system.

This paper presents an algorithm for camera calibration, applying digital images to calculate camera parameters, position and orientation. A linear decomposition technique is proposed to solve nonlinear pixel equations in which camera parameters are involved.

Among many face detection methods the appearance-based ones have proved to be the most accurate and in particular the AdaBoost cascade algorithm is both accurate and a very fast technique. The high speed of the detector is a crucial parameter in many face detection applications, e.g. the face recognition. In this paper the central two-step detector is presented which is a serial connection of the cascade of the extended weak classifiers and the AdaBoost cascade. The cascade of the extended weak classifiers is a novel concept that accelerates the detection speed to a high degree. The second introduced novelty is the verification of the detection results with another AdaBoost cascade to push a number of false acceptances down to the extremely low level.

The influence of low-coherence source parameters on the optical coherence tomography imaging has been studied. Experimentally and theoretically it is demonstrated, that by summing autocorrelation function of two superluminescent diodes with different wavelength, the effective coherent length of the source and signal-to-noise ratio required to identify the central fringe position can be greatly reduced.

The spectral shape of a light source in optical coherence tomography imaging is of prime importance because it determines resolution and quality of the image. Spectra and axial point spread function of photonic crystal fiber light source TB-1550 from Menlosystems GmbH before and after optical spectral shaping are presented. Low-pass and high-pass filters are simulated to shape the irregularities in light spectra of the source. Full-spectrum shaping results with use of spectral processor are calculated. Results show that shaping of a light source improves meaningly axial resolution and inhibits sidelobes of the point spread function.

Fiber-optic low-coherence tomography system with low-coherent reflectometry has been used to non-destructive characterization of ceramics. We presents experimental results showing that the measurements of ceramics internal structure can be done with suitable resolution.

An Optical Low-Coherence Tomography (OCT) is a novel optical measurement technique, which enables non-destructive and non-contact investigation of multilayer structures. Nowadays, this method is highly applied in medical diagnostics. Despite of great progress in optoelectronics and optical measurement methods there is lack of studies on the OCT for non-medical application. In this paper authors present a laboratory OCT system for surface and subsurface investigation of scattering technical objects such as polymer layers. Preliminary test results on subsurface technical objects investigation using OCT system have been presented and discussed.

The aim of this paper is to describe a new Stereovision Laboratory. It was designed and constructed by the authors of the paper in the University of Valencia. It consists of four cameras with its special equipment, a moving track, hardware and software for calculation and visualization. The tests carried out on the measurement stand lead to obtain the set of data describing the movement of human body. The stored data serves to analyze static and dynamic behavior of some parts of human body like arms, legs or vertebral column. Special software was design in order to do visual inspection of the movement and to select a proper data.

The aim of the project was to design and construct a light source for autofluorescence imaging. The source was realized as an add-on device to the endoscope. It is based on semiconductor components: a W LED source and a SMD UV LED. Thanks to the SMD source's small dimensions, as many as 15 diodes could be fitted into the add-on device. This innovative tool can be used for autofluorescence imaging in laryngeal tumour diagnosis.

Medical images are acquired or stored digitally. These images can be very large in size and number, and compression can increase the speed of transmission and reduce the cost of storage. In the paper analysis of medical images' approximation using the transform method based on wavelet functions is investigated. The tested clinical images are taken from multiple anatomical regions and modalities (Computer Tomography CT, Magnetic Resonance MR, Ultrasound, Mammography and X-Ray images). To compress medical images, the threshold criterion has been applied. The mean square error (MSE) is used as a measure of approximation quality. Plots of the MSE versus compression percentage and approximated images are included for comparison of approximation efficiency.

The steady, non-equilibrium, two temperatures model for argon plasma flow is developed. This model is based on the numerical solution of mass, energy and momentum conservation equations using a finite difference method. The modelling results of plasma torch with cylindrical anode of 4 mm diameter and 40 mm length are presented. It operates at atmospheric pressure, 3 slm argon flow rate and 70 A DC.

This paper presents the estimation and the state feedback control of the discrete fractional order states-space systems. First of all the state-space model of a fractional order dynamic system is introduced. For this model the stability condition is derived and discussed. Then the parameters identification problem is presented and least squares solution to it is given. Having established the parameters of the model, in order to produce a state feedback control the state vector is needed. In most cases, however it is not available from measurements. Therefore, the state estimation problem arises. In the paper a modification of Kalman filtering technique for this purpose is proposed. At the end the state feedback pole-placement control is applied to a fractional order system. All the techniques used are illustrated with simulational examples.

The following paper is focused on optimization of data storage for identification of dynamic processes. A method for compression of archived data, containing information about process dynamics without a significant loss of information is described. The proposed algorithm applied to identify TSK models, allows reduction of data amount(approx. factor of l0), efficient data aggregation and archiving.