Effect of impulse noise rejection with median filter on binary digital receiver performance

An analysis of the effect achieved by using a median filter for impulse noise rejection in a binary digital receiver, is carried out. Results have shown that the error probability can be considerably reduced in digital communication systems with a keying speed that is a few times less than is permitted by the channel bandwidth.<>     

Configuration model of matter and its role in theoretical science of materials

The major principles of Samsonov’s quasichemical configuration model are discussed in terms of the many-electron theory of condensed systems. It is shown that the interrelation between the order of the s-and d-levels in isolated atoms of transition elements and the occupation of the corresponding bands in metals can be interpreted with quasiparticle theory that takes the d-d-and s-d-electronic correlations into account more accurately than ordinary one-electron theory does. __________ Translated from Poroshkovaya Metallurgiya, Vol. 47, No. 1–2 (459), pp. 29–36, 2008.     

Making and structural features of Ti-N-B and Ti-N-C nanocomposites

The paper examines the high-pressure sintering of nanograined ceramic polycrystals based on TiN-TiB₂ and TiC_0.5N_0.5 refractory compounds. Using the optimum pressure (up to 4 GPa) allows keeping the initial nanostate (TiN-TiB₂ and TiC_0.5N_0.5) and obtaining high-density ceramics with enhanced mechanical properties. An x-ray structural analysis is used to examine how the TiN-TiB₂ and TiC_0.5N_0,5 crystalline structure evolves during temperature-pressure treatment, which produces new ceramic materials. Based on the properties of the polycrystalline materials obtained, the temperature-time mode for the consolidation of initial nanopowders is determined to ensure favorable parameters of sintered nanograined ceramics. __________ Translated from Poroshkovaya Metallurgiya, Vol. 47, No. 1–2 (459), pp. 62–72, 2008.     

Morphological characteristics of mechanically processed ZnO and MnO2 powder mixtures

The evolution of structural-morphological characteristics of ZnO + 1 wt.% MnO₂ and ZnO + 10 wt.% MnO₂ samples during prolonged mechanical treatment (MT) was investigated by X-ray, AFM, LPS, SEM and IR methods. Changes in crystallite size due to mechanical activation were determined from X-ray measurements. These results were correlated with changes in particle size followed by SEM and AFM. Particle and aggregate size distributions were determined from LPS measurements. Interpretation of the evolution of IR-absorption peaks during mechanical activation using the theory of average dielectric constants enabled analysis of changes of particle and agglomerate shapes. All these results enabled establishment of a relationship between crystallites, particles, aggregates of particles, and superficial processes that occur during mechanical activation.     

An Optical Lock-in Technique as Applied to an Acousto-optic Integrated Spectrum Analyser

Abstract

A new signal coding technique is presented here for use with the existing integrated optical spectrum analyser structure. Modifications to the basic device are implemented, and shown to have a theoretical and an experimental dynamic range increase of 10–20 decibels (dB). Such an increase would bring the overall device dynamic range to 40–50 dB.     

Wideband Acousto-optical Bragg Transducer for Integrated Optics

Abstract

The electrical and acousto-optical characteristics of modified chirp surface acoustic wave Bragg transducers for planar optical waveguides in YZ (Y cut, Z propagating) LiNbO₃ are described theoretically and experimentally.     

A correction of E-model in quality estimation of packetized speech signal

This letter presents correction of E-model for the quality estimation of the packetized speech signal in the case of burst packet loss. The current estimation depends on the method of calculation, i.e. on the duration of speech signal segment, which is to be packetized by one packet. This inconsistency in estimation is described, and the correction of this imperfection is proposed. It is explained that the Packet-loss Robustness Factor is dependent, besides coder, on the duration of speech signal segment, which is packetized by one packet.