N. P. Khvorostenko’s scientific contributions

A hypothesis for the possibility of longitudinal electromagnetic waves in arbitrary media is discussed.

This paper demonstrates the possible existence of electromagnetic solitary waves (SW) in homogeneous linear media with imaginary conductivity, which are localized traveling wave processes. These media include a collisionless ionosphere. The possible existence of SW is based upon a unique relationship between the solution of Maxwell's and Dirac's equations. The problem is reduced to a previously solved problem of the existence of spinor SW, described by spatially localized solutions of Dirac's equation. The field at each space-time point is generated by the superposition of spherical waves radiated by this field at earlier times. This enables one to treat the mechanism of the existence of localized SW as a Huygens mechanism that consists of the reradiation of secondary spherical waves by each oscillator of the medium, which was reached by a primary wave. The solution of these equations show that electromagnetic SW may only be found at the principal Landau Energy levels. The mathematical results obtained in this paper provide a basis for investigating electromagnetic SW.

The comparative efficiency of two well-known methods of unifying parallel demodulation operators, optimally matched to the various conditions of signal reception, into a multioperator adaptive demodulation algorithm, is considered.

Several methods for analyzing the noise immunity of optimal diversity reception in the presence of correlation noise are described. General relations are obtained for calculating the probability of error in the diversity reception of binary signals.

A theoretical account is given of the design and operation of an extractor - a device for the detection of PSK signals. In the input multiplier of the extractor the HF input signal z(t) is multiplied by an LF switching signal b(t). The product is averaged in a narrowband bandpass filter and is multiplied by b(t). The b(t) signal considered here is a random signal in the form of rectangular messages; z(t) is a PSK signal.

(For abstract see issue 03, p. 340, Accession no. A77-14222)

An estimate of the effectiveness of different methods of obtaining diversity reception of correlated signals is given.

It is proposed that the mean duration of intervals of errorless reception be used as the criterion to estimate the quality of radio communication in channels with variable parameters. This criterion is applied to Markov channels with maximum aftereffect, channels with interruption of communication, and channels with signal fading.