Open Access
Access granted
Subscription Access
Vol 59, No 10 (2016)
- Year: 2016
- Articles: 6
- URL: https://journals.rcsi.science/0735-2727/issue/view/10890
Article
Estimation of the optical pulse duration with rectangular intensity profile of unknown height
Abstract
The quasi-likelihood and maximum likelihood algorithms of duration estimation have been synthesized and analyzed. The losses in accuracy of quasi-likelihood estimate caused by a priori lack of knowledge of pulse intensity were also found. The accuracy of the maximum likelihood estimate of duration was found to be asymptotically invariant to the presence of a priori information about the pulse intensity.
427-436
Hybrid electromagnetic-spin oscillations in the ferrite-dielectric structure with single-crystal hexaferrite in domain region
Abstract
Hybrid electromagnetic-spin oscillations in ferrite-dielectric structure consisting of a single-crystal BaFe12O19 platelet and a dielectric disk-shaped resonator in multidomain state of ferrite have been investigated by experiment. Experiments were conducted with different types of domain structures, and the frequency-field spectra were measured at tangent magnetization. It was shown that the effective hybridization of electromagnetic and magnetostatic modes in such resonator could implement such excitation regime, where one electromagnetic mode of dielectric resonator is split into three hybrid quasi-electromagnetic oscillations even in the absence of external magnetizing fields.
437-441
Design of active reconfigurable wheel antenna based on PIN diodes
Abstract
In this paper we suggest a reconfigurable wheel antenna based on PIN diodes. The antenna is excited by a single-feed and operates in S-band and X-band. Proposed antenna’s structure is composed of two circular rings that are excited by multiple PIN diodes and microstrip lines. Antenna’s reconfiguration is realized by inserting switches into spokes and peripheral regions of a wheel antenna. The required resonance frequency is provided by combination of the structures which are controlling by PIN diodes. Developed antenna was fabricated on a RT duroid material and its pattern measurements were carried out in the outdoor environment. The measured results have demonstrated antenna’s ability to be reconfigurated and good radiation pattern characteristics within two frequency bands.
442-448
Influence of ferrimagnetic resonance on conversion of electromagnetic energy into mechanical one
Abstract
In this paper it is obtained in zero approximation the algorithm of calculation of the force of electromagnetic wave propagation in rectangular waveguide applied to the ferrite sphere, placed into constant magnetic field by the method of physical modeling. It is researched the dependence of the force on a value of magnetic field intensity near ferromagnetic resonance. Theoretical results of the calculations were compared with experimental ones. At the resonance electromagnetic field with the power of 10W and the wave length of 3.2 cm influences on ferrite sphere with diameter of 3.55mmwith a force of 6 ± 0.5 µN. This force in enough for rotation of the suspension system of the reference ponderomotive wattmeter, fixed attached by means of braces or kerns. It allows to develop high-precision microwave wattmeters with enough mechanic strength for industrial application.
449-454
High-speed parallel particle filter for PCMA signal blind separation
Abstract
The paper proposes an improved high-speed parallel particle filter algorithm for the blind separation of PCMA-signals by utilizing particle filter’s characteristics of parallelism with the help of a cluster computer system built by using the Matlab distributed computing server and Matlab parallel computing toolbox. The simulation results show that the parallel algorithm can perform the PCMA-signal blind separation quickly and effectively. Further, it can greatly decrease the time of the separation, without reducing the performance of the algorithm, and improve the real-time application of system.
455-462
On the nature of sources of audio-frequency electromagnetic interferences
Abstract
It has been shown that metal elements of electronic equipment executing mechanical vibrations under exposure to the dc or low-frequency magnetic field could be sources of low-frequency electromagnetic interferences. The general solution of a boundary problem of electrodynamics was obtained that dealt with the electromagnetic field emission by a rod with circular cross-section made of metal of the non-ferromagnetic group under harmonic elastic oscillations in the dc magnetic field. A model example was considered for the situation where a source of low-frequency electromagnetic field was the rod with circular cross-section that executed longitudinal harmonic oscillations of compression–tension at the transverse dc magnetic field. An estimation of numerical values of the intensity of low-frequency magnetic field and the induced voltage of interference were also provided.
463-475