Wyniki wyszukiwania - BazTech

1

Analiza efektu dyspersji w modelu antenowym kanału wyładowania atmosferycznego z rozłożoną indukcyjnością

Aniserowicz K.

Przegląd Elektrotechniczny

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2016

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R. 92, nr 2

5--7

PL

Przedmiotem analizy jest model antenowy kanału wyładowania atmosferycznego z rozłożoną indukcyjnością. Dodana indukcyjność jest zastosowana w celu uzyskania odpowiedniej prędkości prądu wyładowania głównego, powodując równocześnie zmiany kształtu fali prądowej wzdłuż kanału. Analiza opóźnienia grupowego w dziedzinie częstotliwości wskazuje, że prędkość propagacji wzdłuż modelu kanału zależy od częstotliwości.

EN

An inductively loaded antenna theory model of a lightning return stroke is analysed. Inductive loading is applied to obtain the required return stroke current speed, which additionally causes changes of the lightning current waveform along the channel. The analysis of the group delay in the frequency domain shows that the propagation velocity along the channel model depends on frequency.

2

Analysis of the Possibilities for Using a Uniform Bragg Grating in a Tunable Dispersion Compensator

Wójcik W., Kisała P., Yussupova G., Kussambayeva N., Kashaganova G., Harasim D.

International Journal of Electronics and Telecommunications

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2015

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Vol. 61, No. 4

381-387

EN

The article presents a tunable fibre optic dispersion compensator system, consisting of a specially designed cantilever beam and a uniform Bragg grating. It analyses the group delay and dispersion characteristics in the case that there is no apodization of the grating and also for a grating with apodization used for modulation of the refractive index. Various apodization parameters were tested, along with their effects on the dispersion characteristics of the entire system properties. It is demonstrated in the paper that the apodization parameter affects the compensator’s group delay characteristic. The finite elements method was used to design a compensator of such a shape that enabled chirp to be induced in a grating of a specified shape. A new design is presented for the system, in which the dispersion properties are tuned by the maximum value of the heterogeneous deformation of the compensator. The paper also includes results showing the effect of the maximum value of heterogeneous stress of the grating on the dispersion characteristics of the proposed construction.

3

On designing a Nyquist FIR filter of fractional group delay and phase delay

Hermanowicz E., Rojewski M.

Elektronika : konstrukcje, technologie, zastosowania

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2014

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Vol. 55, nr 4

17-21

EN

In the paper a novel type of discrete-time FIR fractional delay special filter is investigated. This is a Nyquist filter which, besides the traditional its attribute (intersymbol interference (ISI) free property), has the ability to compensate for subsample transmission delay involved, for example, by dispersive channel. The performance of the filter is analysed and illustrated using QPSK signal.

PL

W pracy przebadano nowy typ dyskretnego filtru specjalnego o skończonej odpowiedzi ułamkowej. Jest to filtr Nyquista, który, poza jego tradycyjną właściwością - braku interferencji międzysymbolowych, jest zdolny kompensować opóźnienia transmisyjne wprowadzane przez kanał dyspersyjny wynoszące ułamek odstępu próbkowania. Przeanalizowano i zilustrowano osiągi tego filtru stosując sygnał QPSK.

4

An efficient method of group delay equalization for digital IIR filters

Okoniewski P., Piskorowski J.

Metrology and Measurement Systems

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2013

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Vol. 20, nr 3

395--406

EN

The paper presents the equalization problem of non-linear phase response of digital IIR type filters. An improved analytical method of designing a low-order equalizer is presented. The proposed approach is compared with the original method. The genetic algorithm is presented as an iterative method of optimization. The vector and matrix representation of the all-pass equalizer are shown and introduced to the algorithm. The results are compared with the analytical method. In this paper we have also proposed the use of an aging factor and setting the initial population of the genetic algorithm around the solution provided by the analytical methodology.

5

Resolving group delay of narrowband optical filters from their transmission characteristics

Śliwczyński Ł.

Opto-Electronics Review

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2009

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Vol. 17, No. 4

318-324

EN

In the paper, the factors affecting the accuracy of calculating the optical filter group delay basing on the measured power transmission characteristic are analyzed. Having the phase characteristic of the filter recovered from its transmission, the group delay is usually calculated via differentiation. The new, direct formula is proposed giving more accurate results when the characteristic of the filter is available in the limited frequency range. Also the limitations arising from the noise of the optical spectrum analyzer are examined.

6

Multi-stage ring resonator all-pass filters for dispersion compensation

Chaichuay C., Yupapin P. P., Saeung P.

Optica Applicata

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2009

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Vol. 39, nr 2

277-286

EN

This paper describes group delay time property of the multi-stage ring resonator all-pass filters (RRAPF) in either cascading single stages or using lattice architectures. The present analysis is restricted to directional couplers and waveguides characterized by various parameters, and careful design of these parameters can optimize the group delay response. The extra phase shifters of each single stage have been adjusted to yield a broadband group delay. By increasing the number of filter stages, a larger bandwidth over the dispersion can be obtained. This device is able to provide dispersion compensation to systems such as the high speed dense wavelength division multiplexer (DWDM) for the optical fiber communication system.

7

Wpływ opóźnienia grupowego na parametry sygnału geostacjonarnego łącza telekomunikacji satelitarnej

Gremba J.

Zeszyty Naukowe Politechniki Świętokrzyskiej. Elektryka

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2005

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Z. 43

59-66

PL

W niniejszym artykule zawarto analizę wpływu opóźnienia grupowego na parametry cyfrowego sygnału geostacjonarnego łącza telekomunikacji satelitarnej. Przedstawiono podstawy teoretyczne opóźnienia grupowego w kanale satelitarnym, koncepcję laboratoryjnego testowania opóźnienia grupowego w łączu satelitarnym. Przeprowadzono analizę symulacyjną wyników pomiarów testowych wszystkich trzech rodzajów opóźnienia grupowego występującego w łączu satelitarnym dla najczęściej stosowanych typów modulacji: QPSK, 8PSK i 16QAM w aspekcie poprawy technologii transmisji sygnału cyfrowego.

EN

Data rates are rising to support skyrocketing demand for Internet traffic, digital TV and other digital services. For satellite operators this means that digital signals are filling their transponders to the limit. To increase throughput operators resort to crowding the available transponder bandwidth and deploying more efficient digital carriers to cram higher data rates into the that bandwidth. As the signals occupy more of the available bandwidth they deteriorate because the transmission path, including the satellite transponder, uplink and downlink equipment, degrade the signal. To make thinks worse, the more efficient high order carriers that support higher data rates are more susceptible to degradation. One impairment that is inconvenient to measure is group delay variation over frequency. It is also hard to find much information on link degradation as a function of the group delay which is required to estimate performance. This paper includes the analysis of the group delay effect on digital signal parameters of the geostationary satellite telecommunication link. It is presented the theoretical background of the group delay in the satellite channel and the testing laboratory conception of the group delay in the satellite link. It was conducted the simulation analysis of test results for each three types of the group delay that are common for the satellite link. The most common types of modulation: QPSK, 8PSK and 16QAM are used in the satellite link both in the digital signal transmission technology improvement aspect.