BIRYUKOV N.L., TRISKA N.R.
Synchronous Ethernet as the basis of time and frequency support of modern and future telecommunication networks
The capabilities and potential of using of synchronous Ethernet as a basis for timing signals and time stamps delivery in packet-based new generation telecommunication networks are considered. The standardization aspects were emphasized.
Key words: time and frequency support, synchronization, synchronous Ethernet, PTP, packet networks, time stamp, ITU-T Recommendation.
RYZHKOV A.V., SAVCHUK A.V., SHVARTS M.L., DRIGA I.A.
Metrology of synchronization in packet telecommunication networks
In contrast of SDH networks where the physical level frequency synchronization is efficient for communication technology time synchronization in packet networks is nessesary for provide the QoS when direct access to clock signal on physical level is absent. Equally with this the adoption of time metrology, new concept, methodology and test sets are imperative. In this paper the features of network synchronization performance measurement in real noise conditions are shown on a base of PTP equipment field test results.
Key words: time synchronization, frequency synchronization (or syntonization), precision time protocol (РТР), master clock (MC), slave clock (SC), packet networks, packet delay variations (PDV).
Synchronization signals’ ensembles in synchronization networks of digital networks, their characteristics and quality monitoring
Ensembles of signals in synchronization networks and the standardization aspects of their generalized quality characteristics are considered. Attention is paid also to the role of the mentioned characteristics in quality monitoring of synchronization networks.
Key words: Synchronization signals, Precise time, Characteristics of synchronization signals. Maximum Time Interval Error, Quality monitoring.
VELICHKO O.N., GOLOVNYA M.V.
Secondary standard of time and frequency units as the source of synchronization signals and time
The work has been reviewed on expansion of the functions of the Secondary standard of the time and frequency units of State Enterprise “Ukrmetrteststandard” as high-precision and high-stable source of time and frequency reference signals and signals of synchronization according national time scale. There has been shown the possibilities of transmission the signals through digital communications channels and the equipment which works according to the protocols of network (NTP) and precision (РТР) time and also the results of testing the РТР equipment on a distance up to 810 km at the real communications networks.
Key words: time scale, synchronization signals, time server, secondary standard of time and frequency units, reference signals.
KOSTIK B.Ya., SHKLYAREVSKY I.Yu., YANKO P.A.
Automatic round-the-clock monitoring of synchronization signals’ stability indicators in telecommunication networks – development and deployment experience
The article reports about wander monitoring system, developed in Ukraine and implemented in Ukrtelecom network, practical results and perspectives.
Key words: wander monitoring, network synchronisation, WMS-8, TIE, MTIE, TDEV.
ZUEV Е.V., RYZHKOV A.V., PELYUSHENKO A.S., SAMATOV V.I., SAKHAROV B.A.
Primary reference source VCH-1008C for using in the digital telecommunication networks’ synchronization systems
The principles of Primary Reference Source VCH-1008C and the possibility of using it as a first hierarchy level clock generator in digital communication networks are considered. There are the main metrological characteristics of VCH-1008C and benefits compared to the previous model VCH-1006C. Key words: clock generator, VCH-1008C, VCH-1006C.
KOSTAREV S.V., LAPSHIN B.A., MATVEYKIN G.V.
Сhanneling equipment of WDM fiber-optic transmission systems
The article considers (as a discussion) an issue of necessity to develop a special channeling equipment of WDM fiber-optic transmission systems where designation of typical WDM channels (herein after standard WDM channels) hierarchy is presupposed. Key words: WDM fiber-optic transmission systems, develop, typical WDM channels.
SULTANOV A.H., VINOGRADOVA I.L., KASHBIEV A.A.
Modeling of fiber-optical interferential conversion device’s design factors
The article is devoted to modeling of the interferential converter design data. The functioning of the device is based on application multibeam interferometer, formed by end faces of a central amalgamation element. Besides, if to execute the amalgamator from an erbium doped material, the device will supply amplification a target signal. The estimation of factor of interferometer mirrors reflection and its geometrical parameters is executed. The device provides also selectivity for spectral components of entrance radiation, that allows to operate of optical radiation chirp.
Key words: optical transfer systems, multibeam interferometer, erbium doped amplifier, chirp of signal radiation, distortion of a digital signal.
Influence of aggressive environment on optical cables’ structural components
The above facts and the experimental results show thatsea water, nitrogen dioxide and ozone have a significant impact on reinforcing elements of optical cables as well as on some polymer materials which are applied as shells of optical cables. Therefore in the design of optical cables and in safety planning it should be taken into account by using appropriate materials and providing initially overstated strength properties of cables considering the successive loss of properties of the reinforcing elements.
Key words: This work shows the results of studies of the influence of aggressive environments, such as sea water, nitrogen dioxide, ozone, ammonia and hydrophobic fillers on functional characteristics of the elements of optical cables.
Nonlinear model of the bipolar transistor with closed traansitions
Reviewed schematics of building control devices amplitude strong harmonic signal bipolar transistors with closed transitions. Known nonlinear model of Hummel — Pune, describing the bipolar transistor in the saturation region, the cutoff of the active region of work, both in forward and in reverse inclusion. This model gives a large error in the calculation of the characteristics of control devices for bipolar transistors with closed transitions.
The paper proposes a nonlinear model of a bipolar transistor, which allows to describe adequately the effect of limiting bilateral high-power signal bipolar transistors with closed crossings and reduce the error in the calculation of control devices based on them.
Key words: harmonic signals, control devices, nonlinear model of the transistor.