KALININ L.B., YAKOVLEV N.A.
Digital television transmitter amplifier non-linearity correction technique
Method of quick pre-correction with known correction programs, based on prior pulse mode amplitude response measurement, is offered. Key words: non-linearity correction, digital television transmitter amplifier, amplitude response.
BEZRUKOV V.N., BALOBANOV A.V., VLASYUK I.V.
Nonlinear distortions of video signal generation in television system
The features of changes in spatial parameters of object video monitoring depending on the distance, viewing angle, height of a television camera’s mount and the coordinates defining the location of the object relative to the axis of its optical projection are investigated. The relation between the nonlinear scale distortions and the decrease of the resolution of television images of objects projected into the boundary regions of intraframe space is shown.
Equations that allow the analysis of characteristics of video monitoring depending on the parameters of objects’ location within the controlled space of videoinformation field are calculated. The resulting equations are presented. The necessity of taking into account changes in shape and scale of controlled objects when developing efficient methods, systems and devices for digital processing, compression of the spectrum and signal transmission of television pictures is shown. Key words: optical imaging, optical-to-electrical converter, vignetting, optical system, scale distortion.
ANPILOGOV V.R., TYRIN P.M., SHUBIN V.I., EYDUS A.G.
Convergence and divergence of technologies and services in Ku- and Ka-bands VSAT networks
The article presents a brief analysis of VSAT technology and features. Particular attention is paid to evaluating the effectiveness of satellite channels. It is shown that the overall technical efficiency of the channel depends not only on the spectral efficiency, but also on the organization of the channel physical and link layers. Analyzes the technologies and services in bulk networks VSAT. It is shown that the convergence of technologies and services in VSAT networks should be based on their technical analysis, ensuring the identification of differences that affect the quality of services. Key words: VSAT, channel, organization, identification.
Landau-Plazhek ratio measurement optical reflectometer
The actual problem of cable replacement length determination for optical cable link restoration is considered. It is shown a non-expensive field-condition portable instrument for localization of fiber optic cable delivery length fragments under mechanical strain more then 0.1 – 0.3% is required. Potentialities of those instrument realization based on measurement of Landau-Plazhek ratio (LPR) are demonstrated. It is shown the optical LPR-reflectometer under the same price, comparing to conventional OTDR, will be actual on the market of measurement equipment for optical cable testing during manufacturing, installation and maintenance. Key words: optical fiber. optical cable. optical reflectometer. Landau-Plazhek ratio. Q-switch laser. Mach-Zander interferometer. coherent receiving.
DSL access in stars quad NF networks
This work paper is analysing networks built with low-frequency cables (star quad). By analysing the influence of return losses on total attenuation of pairs in the last step, the author emphases limits for broadband (DSL). Also, analysis of the influence between the pairs inside the A group (diagonal of chess field) shows which „NEXT“ has dominant effect on „PS NEXT“ in A group for broadband DSL. Author is giving the proposal how the existing low-frequency networks (star quad) to make capable for broadband DSL. Key words: Broadband DSL, low-frequency cables, star quad, MSAN, elektromagnetic bridge star quad, Attn, Return Loos, NEXT, PSNEXT, A group, PSACR, SNR.
NANIY O.E., NOVIKOV A.G., PLOTSKI A.Yu., TRESHCHIKOV V.N., UBAYDULLAEV R.R.
Characteristics of a multispan DWDM system with 40 Gbit/s DPSK channels in a grid of 50 GHz
Characteristics of a multispan DWDM-communication system with a speed 40 Gbps with differential phase modulation (NRZ ADPSK format) were experimentally investigated. Required optical signal to noise ratio (OSNR) dependence from distance, capacity of a signal, the dispersive plan, and distance between channels is investigated.
For length of line 2000 km at optimum power required OSNR is 12,5 dB, and measured OSNR at the end of a line is 20,5 dB. OSNR budget is 8 dB that allows us to estimate the maximum length of line as 5000 km. Key words: optical communication, wavelength division multiplexing (WDM), differential phase modulation, optical signal to noise ratio (OSNR), nonlinear distortions, crosstalk.
Fireproof optical cables: problems and solutions
The work shows the relevance of fireproof, non-flammable, low-smoky and non-toxic optical cables; systematizes categories of assessment of indicators of fireproof materials in according with various standards; makes recommendations on the design of fireproof and flame-resistant optical cables and the application of the appropriate materials; describes the designed construction of the fireproof optical cable. Key words: optical cable, fire safety, non-proliferation of combustion, constructional elements, flameproof, low smoky gassing.
ZARUBIN V.K., LOKSHIN B.A., ORLOV Yu.Yu.
Technical resources for arranging Ka-band trunk-line satellite channels