Wyniki wyszukiwania - BazTech

1

Szerokopasmowy mikrofalowy układ pomiaru różnicy faz sygnałów

Kachel Leszek

Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

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2019

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nr 7

590--594, CD

PL

W artykule przedstawiono wybrane rozwiązania układowe mikrofalowych dyskryminatorów fazy (MDF) oparte na sprzęgaczach kierunkowych Lange’a oraz wieloliniowych sprzęgaczach wielowarstwowych. Wroli szerokopasmowego przesuwnika fazy zastosowano przesuwnik fazy na niesymetrycznej linii paskowej z wtrąconymi niejednorodnościami i przesuwnik fazy ze strukturalnym skrzyżowaniem linii. Ponadto przedstawiono rezultaty analizy teoretycznej wraz z wynikami pomiarów dla wybranych modeli dyskryminatorów fazy w paśmie 2-4GHz.

EN

The article presents selected system solutions for microwave phase discriminators (MDF) based on Lange's directional couplers and multi-line multi-layer couplers. As a wide-angle phase shifter, a phase shifter was used on an asymmetrical stripline with embedded heterogeneities and a phase shifter with a structured intersection of lines. In addition, the results of theoretical analysis together with the results of measurements for selected models of phase discriminators in the 2-4GHz band were presented.

2

Measurements of Concentration differences between Liquid Mixtures using Digital Holographic Interferometry

Guerrero-Méndez C., Saucedo-Anaya T., Araiza-Esquivel M., Balderas-Navarro R. E., López-Martínez A., Olvera-Olvera C.

Metrology and Measurement Systems

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2017

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Vol. 24, nr 1

19--26

EN

We present an alternative method to detect and measure the concentration changes in liquid solutions. The method uses Digital Holographic Interferometry (DHI) and is based on measuring refractive index variations. The first hologram is recorded when a wavefront from light comes across an ordinary cylindrical glass container filled with a liquid solution. The second hologram is recorded after slight changing the liquid’s concentration. Differences in phase obtained from the correlation of the first hologram with the second one provide information about the refractive index variation, which is directly related to the changes in physical properties related to the concentration. The method can be used − with high sensitivity, accuracy, and speed − either to detect adulterations or to measure a slight change of concentration in the order of 0.001 moles which is equivalent to a difference of 0.003 g of sodium chloride in solutions. The method also enables to measure and calculate the phase difference among each pixel of two samples. This makes it possible to generate a global measurement of the phase difference of the entire sensed region.

3

Evaluation of Uncertainty of Phase Difference Determination in Presence of Bias

Saranovac L. V., Vučijak N. M.

Metrology and Measurement Systems

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2016

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Vol. 23, nr 4

603--614

EN

Determination of the phase difference between two sinusoidal signals with noise components using samples of these signals is of interest in many measurement systems. The samples of signals are processed by one of many algorithms, such as 7PSF, UQDE and MSAL, to determine the phase difference. The phase difference result must be accompanied with estimation of the measurement uncertainty. The following issues are covered in this paper: the MSAL algorithm background, the ways of treating the bias influence on the phase difference result, comparison of results obtained by applying MSAL and the other mentioned algorithms to the same real signal samples, and evaluation of the uncertainty of the phase difference.

4

Numerical research of the viscous effect of the bilge keel on the damping moment

Deng R., Duan W., Ma S., Ma Y.

Polish Maritime Research

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2015

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S 1

67--74

EN

Bilge keels are effective passive devices in mitigating the rolling motion, and the usage of them covers almost all the sea going vessels. This paper focuses on the viscous effect of the bilge keel, ignored the effect of the free surface and the effect of the ship hull, for the general viscous characteristic of the bilge keel. In order to investigate the viscous effect of the bilge keel on the total damping moment, a special 2 dimensional numerical model, which includes a submerged cylinder with and without bilge keels, is designed for the simulation of forced rolling. Three important factors such as bilge keels width, rolling periods, as well as maximal rolling angles are taken into account, and the viscous flow field around the cylinder is simulated by some codes based on the viscous method in different conditions, in which the three factors are coupled. Verification and validation based on the ITTC method are performed for the cylinder without bilge keels in the conditions of different rolling periods and maximal rolling angles. The primary calculation of damping moment induced by the cylinder with 0mm, 4mm, and 10mm width bilge keels shows some interesting results, and a systematic analysis is conducted. The analysis of the damping moment components suggests there is phase difference between the damping moment induced by the cylinder and the bilge keels, and when the bilge keels width reaches a special size, the total damping moment is mitigated. The calculation of the damping moments induced by the cylinder with some larger bilge keels are also performed, and the results suggest that, the damping moment induced by the bilge keels is increased rapidly and becomes the dominant part in the total damping moment while the width of the bilge keels are increased, but the damping moment induced by the cylinder is not changed significantly. Some illustration of the vortices formation and shedding is included, which is the mechanism of the damping moment caused by the bilge keels. The present work shows an interesting problem, and it is useful for the bilge keel design.

5

Fine structure of heterogeneous vector field and its space averaged polarization characteristics

Brandel R., Mokhun A., Mokhun I., Viktorovskaya J.

Optica Applicata

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2006

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Vol. 36, nr 1

79-95

EN

Interrelation between the fine structure of the vector field and its averaged polarization characteristics is considered. It is shown that space averaged Stokes parameters are defined by dispersion of the phase difference (or dispersion of the polarization azimuth) at its saddle points. At the same time the dispersion of the phase difference is directly related to averaged space between the nearest adjacent component vortices of the same sign, which are associated with the different orthogonal linearly polarized components. The dependence between the dimensions of areas where considerable polarization changes occur and averaged space between the nearest adjacent component vortices of the same sign is obtained. The results of computer simulation and the experimental investigation are presented.

6

Transformation of polarization state of the light using wave plates with arbitrary phase difference: half wave plates

Woźniak W. A., Ratajczyk F.

Optica Applicata

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2003

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Vol. 33, nr 2-3

337-343

EN

The practical problem of the lack of a quarter-wave plate for an arbitrary wavelength has been solved in our earlier work. The possibility of substituting this plate with a combination of two (or more) retardation plates with phase shift different from 90° has been shown. However, there are some special cases in which another wave plate commonly used in polarization optics is needed, i.e., a half-wave plate. In the present paper some formulae have been derived for several of the most important applications of these retardation plates in measuring setup.