ISSN 1210-2512 (Print)

ISSN 1805-9600 (Online)

Radioengineering

Radioeng

Proceedings of Czech and Slovak Technical Universities

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June 2000, Volume 9, Number 2

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K. Danek [full-text]
Efficient Use of Mobile Radio Channels II

This paper is focused on the use of the mobile radio channels, comparing the efficiency of analog double-conversion superheterodyne receiver and software radio. The task of mutually comparing both technologies is made difficult by the possibility of implementing various decoding algorithms. Hence, the criterion of the dynamic range is being postulated as a basic comparison. The data-bearing signal which got degraded in sequel of unfit parameters - those which in their sum characterize the dynamic range of the receiver - cannot be renewed and faultlessly decoded anymore.

D. Kula [full-text]
Fundamentals of an Optimal Multirate Subband Coding of Cyclostationary Signals

A consistent theory of optimal subband coding of zero mean wide-sense cyclostationary signals, with N-periodic statistics, is presented in this article. An M-channel orthonormal uniform filter bank, employing N-periodic analysis and synthesis filters, is used while an average variance condition is applied to evaluate the output distortion. In three lemmas and final theorem, the necessity of decorrelation of blocked subband signals and requirement of specific ordering of power spectral densities are proven.

P. Kvarda [full-text]
The Importance of Simulation Accuracy in Chaotic Circuits

In this paper an example of importance of the simulation accuracy in deterministic chaotic oscillators and other chaotic systems is briefly described and shown. Low accuracy in simulation may cause that the non-chaotic system may look chaotic or chaotic as non-chaotic. How we can prevent it is shown also in this work.

M. Babincova, P. Cicmanec, P. Babinec, V. Altanerova, C. Altaner [full-text]
Magnetoliposome Mediated Local Electromagnetic Tumor Hyperthermia

Magnetoliposomes prepared by enwrapping 8 nm sized superparamagnetic magnetite grains with phospholipid bilayer were evaluated as possible new material for local electromagnetic hyperthermia both in vitro and in vivo after their injection into implanted BP-6 tumor in rats. As has been found the center of tumor is heated in 10 minutes from 35°C to 44.1°C using magnetic field with induction 1.5 mT and frequency 3.5 MHz.

P. Sadovsky, K. Bartusek [full-text]
Optimisation of the Transient response of a Digital Filter

The paper presents a theoretical analysis of the method that enables optimisation of the transient response of a digital filter or of an arbitrary discrete system, by pre-setting the initial conditions of the inner state description. For a particular design of a filter, it is enough to once evaluate coefficients, multiply them by the magnitude of the first sample of the signal and do filtration by using these initial conditions. The method was verified using the simulated, and NMR signals to maintain spectrum baselines correction, and will also be used for the study of an optimum filtration of the NMR signal with a variable instantaneous frequency.

J. Zavacky, J. Mihalik, M. Kapinos [full-text]
Resampling of an Image by Block-Based Interpolation or Decimation with Compensation

Due to multiple standards on digital coding of image it is expected that conversion from one picture format to another will be quite necessary for display or recording of different format sources. Conventional approach of 2-D sampling rate conversion by polyphase filters requires relatively large memory and computational power. Therefore, a new efficient method for image resampling has been presented. The proposed approach performs resampling block by block with overlap. To minimize the overlap special block interpolation kernels are used, with one pixel overlap gives satisfactory result for most of practical images. Proposed method can be efficiently applied to image communication systems where block transforms are used for data compression.