Jiri Drinovsky

High frequency chaos converters

The aim of this paper is to prove an interesting feature of some simple second-order dynamical systems with an external AC force called chaos-based signal conversion. To do this, algebraically simplest case of mathematical model has been selected and corresponding spectrum of the Lja-punov exponents (LE) has been calculated. Finally an electronic circuit suitable to model such behavior is derived and its correct function is experimentally verified.

Virtual Anechoic Room An Useful Tool for EMI Pre-Compliance Testing

The paper deals with principles of so-called virtual anechoic room, which presents an economical and accessible possibility of ambient signal elimination in open field test site (OFTS) EMI measurement. Some variants of easy and efficient EM ambient cancellation are described and some measurement examples are presented in the article. In general, the radiated and conducted EM measurement based on principle of virtual anechoic room performs sufficiently accurate results without the need of dedicated and cost expensive OFTS or anechoic chamber.

Variable Impedance in Measuring EMI Filter’s Insertion Loss

This paper deals with problems concerning variable impedance of power lines in the measurement of insertion loss of EMI filters. A circuit which represents variable power line impedance was designed and was added into the normal measuring structure of EMI filters. This was applied to an asymmetrical and a non-symmetrical measurement technique. The design, structure of measurement and results obtained are explained in this paper

Slow Data Rate Sequence Satellite Ranging

In this paper a simple newly developed semicoherent slow data rate ranging application for small satellites is described. Ranging, as a set of methods for satellite tracking, is a very important part of most of the satellite systems and the space missions. Firstly, a brief overview of the most commonly used ranging methods is presented. After that, a semicoherent ranging system is described that has to be implemented in a simple experimental system for feature testing using a simple linear transponder of an AMSAT satellite phase-3E and phase-5A probe. Practical test range measurements via FO-29 satellite have been carried out by this system

Influence of the probe position to disturbance measurement in the Workbench Faraday Cage

The Workbench Faraday Cage measurement method is a well known way, how to measure disturbance caused by integrated circuits mounted on PCB. This paper deals with simulation of this method provided by FORTRAN FDTD code. This work explores the influence of harmfull signals to measurement probe position and proposes a main theses, how to connect measure probes properly. Effect of opened Faraday Cage is also simulated.

A New Measuring Method Suitable for Measuring Shielding Efficiency of Composite Materials with Carbon Fibers

This paper deals with the theoretical and practical aspects of the measurement of shielding efficiency. An alternative method of these measurements is described in this contribution. The theoretical design, the measured results and parameters of measurement circular flange are discussed in other parts of the paper. Carbon fibers are electrically conductive and can be added to cement to enhance the shielding effectiveness. The paper describes possible methods for measuring shielding efficiency of concrete materials with carbon fiber.

Automation Measurement Setups for EMC Laboratory Course

This paper describes a new form of the laboratory exercise in electromagnetic compatibility course at the Department of Radio Electronics in the bachelor study program. Four exercises were modified by using the Agilent VEE Pro graphical language software. Students measure the tasks in laboratory exercises using the personal computer with appropriate program which commands the measuring instruments. Students have to build their oven small and simple programs for commanding the measuring instruments. Students widen their knowledge about automation of measurements in EMC laboratory by exercises modification and also compare the efficiency of the automation measuring system with manual measurements.

Operation Amplifiers in EMI Filter Insertion Loss Measurement Setup

The paper deals with the measuring of the EMI filters insertion loss. Two variations of differential mode measurement setups are compared. Impedance transformers are used in the first setup. Active devices (operational amplifiers) were used in alternative measurement setup instead of impedance transformers. This replacement was done for the 50 Omega differential mode insertion loss measurement setup. The performance of modified measurement setup was tested on several single phase EMI filters. The obtained data were compared with data taken in the setup with impedance transformers.

Feature Selective Validation of Automotive EMC Pre-compliance Tests

The pre-compliance tests of electromagnetic immunity are at present a crucial issue for all major automotive manufacturers. In current practice, there are two basic ways to implement these tests. The first one is based on significant simplification of measurement methods and the subsequent transformation of results for relevant estimation of certification measurement results. The second is based on the application of numerical methods and the calculation of the electric field intensity distribution in the car body. The question, however, remains the degree of correlation between these methods, especially when confronting the results of certification measurement. This article provides an overview of the results obtained using both methods and offers an innovative view of the method of comparison using the FSV.

Modification of approximate worst-case measurement system for EMI filters

This paper deals with the approximate worst-case test method for testing the insertion loss of the EMI filters. The systems with 0.1 Ω and 100 Ω impedances are usually used for this testing. These measuring systems are required by the international CISPR 17 standard. The main disadvantage of this system is the 0.1 Ω impedance transformer. The dynamic range for the transformation from the 50 Ω, which is most common matched impedance for the measurement setups, to 0.1 Ω is very large. It is no easy to produce such transformers with this high impedance transformation ratio. These transformers have usually very narrow bandwidth. This paper discusses the alternative system with 1 Ω and 100 Ω impedances. The performance of these systems was tested on several filters and the obtained data are depicted, too. The performance comparison of several filters in several systems is also included. The performance of alternate worst-case system is discussed in the conclusion.