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We propose a method of interperiod signal processing, which is based on the projection Doppler filterting method and used for selection of moving targets. The scheme of using the algorithm of the proposed method for signal processing is presented. The efficiency of this algorithm is assessed with regard to the optimal algorithm of matched filtering for various lengths of signal sampling.

We consider the method of formation of adaptive threshold of signal detection against the background of receiver inherent noise using the nonparametric algorithms on the basis of ordered statistics. The simulation results and the efficiency of using this method on the basis of estimating the quantiles of the statistical distribution of the process compared with the classical methods of “moving average” in the case of complicated signal-interference environment (weak-signal masking by intense interference, mutual masking of several signals simultaneously staying in the sliding data window, and the useful-signal presence in the region of the jump-like variation of interference) are shown. A mathematical model of estimating the loss introduced when detecting a useful signal by the threshold device based on the method of ordered statistics is developed.

We present the results of measuring the coefficient of specific attenuation in supercooled water in the pores of silica gel at a frequency of 34 GHz in the temperature range from +20°C to −190°C. It is shown that in moistened silica gel with nanosized pores, noticeable radiation losses occur down to a temperature of about −100°C. This is due to the presence of a certain amount of liquid water in the pore space. Part of the water, which is strongly bound with the surface of the pores, does not freeze at temperatures down to −136°C, at which vitrification takes place. The properties of the other fraction, which is weakly bound with the surface are close to that for the volumetric water, i.e., it crystallizes completely on being cooled down to the critical temperature −(38–45)°C, which is determined by the properties of the surrounding medium. Absorption of the electromagnetic radiation in supercooled water captures in pores should be allowed for, e.g., in the problems of radiation transfer in an atmospheric moistened aerosol, especially in the millimeter wavelength band.

We have developed methods for adaptation of the modulation radiometer under the conditions of a priori uncertainty of the temporal distribution of pulsed interference. Two ways of forming the reference voltage are proposed: one according to the measured time parameters of the pulse interference and anther according to the current parameters of the pulse interference.

We consider two phenomena that are typical of the volume superimposed holograms, namely, the formation of the dielectric-permittivity structures corresponding to interference of the reference waves, which did not interfere in reality, due to the nonlinearity of the medium, and double diffraction of the waves in the hologram volume. It is shown that when the holograms are recovered, these mechanisms form associations between the waves which are not linked explicitly by virtue of the different-time record of individual holograms. The strengths of the associative links are proportional to the scalar product of the signal images. A neural network model that allows for the described mechanisms as related to recording of the volume superimposed holograms using the Fourier holography scheme with plane off-axis reference beams is proposed.

We consider the possibilities of the aperture synthesis using a single moving receiver during direction finding of the sources emitting a random stationary narrowband signal. It is shown that in this case the coordinates and projections of the source velocities can be determined from the current estimates of the Doppler frequency shift. Using the Cramer–Rao bound, we analyze accuracy of determining the parameters which characterize the rectilinear trajectory of the source during the circumferential receiver motion as functions of the synthetic-aperture size, emittedsignal bandwidth, signal-to-noise ratio, etc. Possible applications of the proposed version of the aperture synthesis in underwater acoustics and radio astronomy are considered.

We consider the problem of calculating the reflection function for the case of radio-wave propagation in a stratified inhomogeneous absorbing ionosphere. A stable method for calculating the reflection function is proposed. Examples of calculations by the proposed method are shown for symmetric and parabolic ionospheric layers.

We consider scattering of a narrow optical beam in a scattering medium by a randomly rough surface with Lambert indicatrix of local scattering. Expression for the average power of a signal recorded by the receiver is found for the Gaussian distribution of heights and rough-surface tilts. The obtained formala makes it possible to correctly describe the received-signal power both in a transparent and optically dense atmosphere. It is shown that in the bistatic sounding scheme, the received-signal power significantly depends on the surface heights variance.

We present the results of experiments with a CW single-mode Nd:YAG laser, tunable in the vicinity of 1064 nm, with an intracavity narrow-band Cs 2 vapor saturable absorber. It is shown that the laser dynamics is determined by both the pump level and detuning of the laser frequency from the absorption-line center.

We propose the method of a “shifted” meter for monitoring the temperature regimes during the spot heating of materials and present the results of an experimental study of the proposed method in the case of the electron-beam welding of zirconium pipes in vacuum.

We present the results of a study and substantiation of the method of polygaussian approximation of an electrocardiographic (ECG) signal against interference background during computer analysis of that signal. It is proposed to use adaptive processing of ECG signals, which allows one to increase the signal-to-interference ratio by over 7 dB.

We measure the dielectric parameters of frozen sand by using a rectangular cavity resonator at frequencies 5.3–8.4 GHz. The transmission spectrum of the resonator completely filled with frozen sand shows supplementary resonances absent in the case where the resonator is filled with dry homogeneous sand. The difference of the resonance curves was observed for the cases of wetting the sand by ordinary (H2O) and heavy (D2O) water. It is supposed that the observed effects are related to percolation due to the existence and specific properties of the conducting liquid films of water on the surfaces of mineral particles. To verify this assumption, we performed measurements for the special medium consisting of a mixture of dry sand and small metal particles. This experiment showed that supplementary resonant peaks in the transmission spectrum of the resonator arise for a certain concentration of metal particles. The same effect is also observed in the case of incomplete filling of the resonator with dry sand. These anomalies can be explained by the appearance of negative dispersion of waves in the waveguide.

Some characteristics of Cassegrain optical systems, consisting of two spherical mirrors, are considered. Based on simulations in the geometric-optical approximation for a wide range of parameters, we find the relationship between the geometry of an optical system with an extended thermal receiver and the main-lobe width of the angular distribution of the system power. This permits one to optimize the system design on the basis of its performance requirements. We determine the optimal displacement of the small mirror from the quasi-focal area of the large mirror, ensuring the minimum main-lobe width in terms of a given level and a given dissipation factor.

We solve the problem of determining unknown information parameters of a process having continuous and pulsed components. It is proposed to modify the maximum likelihood method (MLM) on the basis of threshold statistics with an adaptive threshold. We compare the properties of the determinant of information parameters of the process with continuous and pulsed components using the MLM and threshold statistics with and without an adaptive threshold. The quasioptimum receiving device for estimating the above parameters is synthesized.

We present the results of theoretical and experimental studies of the field structure of a distributed flexural-wave antenna. The efficiency of mechanical-acoustical transformation in such an antenna and the prospects for its applications in ultrasound systems of nondestructive testing are estimated.