Vol 20, No 2 (2017)

The article considers the construction of mathematical models of vibrator antennas with a large cross-section on the basis of thin-wire integral representations of the electromagnetic field. A mathematical model of a thin-wire vibrator is obtained, equivalent to the model of a tubular vibrator. It is shown that taking into account the rotational symmetry of the structure in the fine-wire integral representations of the electromagnetic field when solving the internal electrodynamic problem leads to the Fredholm integral equation of the first kind, and not to the singular integral equation, which takes place when using the tubular model. The results of calculation of current distributions on thin conductors forming a vibrator are presented, as well as the dependence of their input resistance on the electrical length of the vibrator.

The article presents the operating principles, evaluation of metrological characteristics and embodiments for microwave photonics probing of similar FBG interrogator based on frequency shift interferometry and variation of difference frequencies. It is shown, for the first time, the possibility of using them in dual-frequency probing radiation format, when latter received via microwave amplitude-phase conversion of the optical carrier by the Il’in-Morozov’s method. The prospects of these methods use in the structure of the fiber-optic sensor-networks are discussed.

The principles of a construction of a modern receivers of a reference frequency and time signals, included GLONASS/GPS signals, are considered in this paper. A mathematical model of the synchronization system of the receiver-comparator was proposed, and the results of its analysis and its modeling was leaded.

The methodology and algorithm for obtaining verification results are proposed. The algorithm includes five steps: choice of parameters for cluster analysis algorithms, determination of the initial data by the results of the training experiment, conversion of source data, determining the composition of the cluster groups, calculation of verification accuracy. A sample of CMOS type chips was used for the training experiment. The dendogram is the result of calculation for the hierarchical classification. The composition of each of the clusters was determined. Verification results are presented for nine variants.

The principle of an x-ray tomography is considered. Some laws of x-ray radiation and organism tissue interaction are submitted. How on the basis of Radon’s transformation form the projective data for reconstruction of the image in a computer x-ray tomograph there are shown. Theoretical bases of the projections forms and reconstruction of axial-symmetrical pathological focus are presented.