The task of time selection of the signals from individual radio emission sources (RES) occurs at the station of radio control (RC) whenever at the entrance of the analyzing device combines signals from multiple sources. This problem is solved using a search algorithm [2]. However, this algorithm does not work reliably, if the pulses from the several (usually 3-5) RES present in the mixture. In this case, the probability of forming false estimates of the input sequences. The purpose of this article is to develop an improved algorithm for time selection with a higher accuracy of signal separation in the complex electronic environment. Classification of signals by referring to the wobble of pulses repetition period in the sequence, including the sequence with constant value of the period, dwell and switch, stagger, sliding, wobulaten and jittered sequences are given. Based on the classification improved algorithm for the allocation sequence is developed. The algorithm (Fig. 3) provides analysis of the histogram of the values of the delays between the adjacent pulses of the input mixture. The most probable values of the periods of repetition is allocated on the basis of the analysis of changes in pulses which are related to the signals, composed the mixture. The allocation is from the simple to the more complex signals. After the detection of the individual signal in's pulses are removed from the mixture, and the analysis is repeated. The results of the processing of signal (Fig. 6), including pulse sequences from several sources (Fig. 5) are given.

A processing system of multi-frequency signals on the background of correlated (passive) interference is considered. The article presents a comparative analysis of characteristics of multi-processing systems of interperiod processing with various multiplex systems on coherent rejection of interference and subsequent non-coherent accumulation of rejection results. The criteria used in the analysis are high-speed and power characteristics as well as processing system detection characteristics. The analysis of the various options for building of multi-frequency interperiod processing systems with non-coherent accumulation makes it possible to evaluate the advantages and disadvantages of these systems. Frequently practiced algorithm of interference rejection after multiplexing provides the best speed performance, but it gives way to the schemes carrying out interference separate rejection in each frequency channel, which, in turn, can significantly improve signal detection conditions for blind target speeds as compared to single frequency systems.

In this paper three methods of interferences nulling for GNSS GPS or GLONASS are described. A digital antenna array for compensation of interferences is implied. Two methods are based on the eigenvector decomposition of the correlation matrix of received oscillations. An expansion of the correlation matrix on its eigensystem is applied. The eigenvector matrix must be divided on the noise and signal subspaces. Some main components of the eigenvector matrix are used to weight vector calculation. The structure of a space-time interferences compensator is shown. The comprehensive test and the comparative analysis of effectiveness of described methods with the classic gradient method of output fluctuation power minimize under restriction on radiation pattern are completed. A suppression coefficient ranges up to 60 dB.

When electric filter designs "on the whole" circuit's parameters are determined as a result of solving the system of equations formed by equating of coefficients at equal powers of the variable in terms of desirable transfer function (TF) and TF filter. The solution of the system of nonlinear equations is the set (or sets) of filter parameters. The transition to practical realization requires bringing the filter parameters to the standard range of nominal values. The frequency responses of the filter are distorted, when the calculated values are replace on the nominal values. Moreover, the nominal value scales themselves have different range of values depending on the selected range. The purpose of the article is to develop evaluation methods of amplitude- and phase-frequency responses resistance of low-pass and high-pass filters to parameter variations during the filters realization. The integral square function of a variable is taken as a measure of deviation of the real frequency response from calculated characteristic. The specific parameter response resistance is defined as the inverse average value of the integral function at the given range of the parameter variations. The inverse sum of average values of the integral function for the specific set of elements serves as integrated evaluation of response resistance to the filters parameter variations. In case there are several solutions of the system of equations, providing filter synthesis, the one should be used that gives closest to the maximum value of integrated evaluation of resistance. The introduced definitions allow to fulfill the successive selection of filter elements in the light of the impact of each element in the total evaluation of the frequency response stability.

To design and analyze signal processing procedures in the onboard receiver of a space-based altimeter an analytical echo-signal model is desirable which combines compactness with acceptable accuracy of presenting average return power dependency on the measured parameters. On the same premises as for the popular Brown’s model and for the scenario of a sharp antenna beam the expression is proposed linking the mean return power profile to parameters to be measured: orbit altitude, significant wave height and antenna boresight angle. Only the “ready” functions enter the equation obtained, so that no numerical integration is necessary. The model proposed is feasible to optimize echo-signal search and tracking algorithms as well as to evaluate the potential accuracy of joint estimate of the abovementioned parameters.

In the analytical approximation of time dependent average power of a satellite altimeter echo-signal (power profile) the Doppler scattering of individual specular point responses is usually neglected. Meanwhile, in the modern Ka-band altimeters the Doppler shift of reflection from a point near illuminated spot edge is greater than the frequency resolution. The equation for the power profile allowing for the Doppler effect is derived. While, as expected, the profile leading edge is not influenced by the Doppler shift, there is critical discrepancy in the trailing edge behavior between ranging LFM and BPSK signals. If for the former the Doppler shift involvement does not change trailing edge steepness for the latter it makes the profile decrease much faster. Finally, the possibility to utilize the Doppler scattering to improve along-track altimeter resolution is discussed.

A single model for the formation of two-level and multi-level oscillations with envelopes of different shapes using the methods of passive digital frequency synthesis are considered. A comparative analysis of the spectra of oscillations at the output of the system of two-level and multilevel passive digital frequency synthesis is made. The mechanisms of interference generation in the spectrum of the output oscillations with multilevel frequency synthesis are analyzed for the case of the perfect output digital-to-analog converter (DAC), with the bit width fractional multiple to the bit width of the phase accumulator (FA). It is also shown that additional spectral components appear, which are absent at the integral bit width relation of DAC and FA.

Increase in quantum efficiency of silicon image sensor in the short-wave infrared range 900…1100 nm is shown theoretically and confirmed experimentally in case of temperature increase of a crystal. This increase is caused by reduction of width of the forbidden band of silicon in case of temperature increase of a crystal from +50 °C to +130 °C. The experimental study of the dark currents showed that for CMOS-sensors of Sony their value anomally small up to temperature of +130 °C. Thus, optimization of temperature of a crystal of the image sensor by criterion of the relation signal/noise is possible. It is set that in case of temperature increase of a crystal to +80 °…+120 °C the relation signal/noise by operation on wavelength of 1064 nanometers increases in 2 … 3 times.

The problem of infinite array of slot impedance loads with dielectric coating excitation by plane wave is considered with the purpose of determining the equivalent surface impedance. Each array element consists of three areas and The area is the half space above the delimiter boundary. In this area the primary field is excited by the plane wave. The area does not contain any excitation sources and consists of dielectric layer of t thickness located between the planes and The area does not contain any excitation sources either and is bounded by parallel-plate waveguide walls with the distance b between them. The area is connected with the area by one or several slots in the top wall of the parallel-plate waveguide placed on the boundary of volumes and . A plane conductor is placed in the aperture of each slot. Excitation source characteristics and construction parameters do not depend on z coordinate (2D-problem). The problem is solved by the integral equation method and is calculated by the Krylov-Bogolyubov method so that the integral equation is reduced to the system of linear algebraic equations. To overcome mathematical difficulties dealing with logarithmic singularity in the kernel of the integral equation Kummer transformation is used. This allows not only improving the series convergence but also getting the logarithmic singularity in explicit form and integrating it analytically. Numerical results are given as equivalent surface impedance dependencies on the construction geometrical dimensions for fixed values of the averaging interval, the plane wave incidence angle and the thickness of the dielectric layer. It is shown that equivalent surface impedance can be varied by changing the slot width and the plane conductor width. A comparative analysis of the obtained dependencies possessing impedance load characteristics with no dielectric coating is carried out.