National Repository of Grey Literature 51 records found  beginprevious21 - 30nextend  jump to record: Search took 0.01 seconds. 
Assembly of optical cables - effect on fiber parameters
Zelinková, Vlasta ; Křepelka, Václav (referee) ; Filka, Miloslav (advisor)
The aim of this paper is to describe the optical fiber manufacture, installation, utilization in practice and the parameters that affect its properties. The practical part was devoted to the creation of optical paths, the implementation of separate and subsequent measurement and evalution of the resulting values. Finally, the comparison is to measure fair values of laboratory measurements and tracks how much influence can have errors in the construction of optical lines to fiber parameters.
Optical cables in modern data centres
Hejtmánek, Ondřej ; Křepelka, Václav (referee) ; Filka, Miloslav (advisor)
The essence of this study was to evaluate the issue of fiber optic and data cables in modern data centers. To compare and evaluate optimal design parameters were chosen as follows: Performance, reliability, installation time, flexibility, weight and size, requirements maintenance and training and the total price. The introductory chapters describes structure of the data center and network bases and storage technologies used in data centers. Particularly a local area network Ethernet and storage technology, DAS, SAN and SAS. Followed by a metallic and fiber optic cabling. For metallic cabling are used primarily PiMF cables. The fiber optic cabling emphasis was placed on multimode fiber OM3 and OM4. The main point of this study was to compare three types of installation metallic and three types of fiber optic cabling. MRJ-21 solution, pre-terminated system and standard installation of the so-called notch technique for metallic cables. For optical cabling has been chosen MPO solution, pre-terminated system and standard installation by welding fibers. In the end were compared and evaluated various solutions. The main focus was placed on the parameters of performance, reliability and installation time. The optical systems were rated the best solution MPO and preterminated system. Results were similar for the metallic cabling, where most of the parameters of the solution satisfies MRJ-21 followed by pre-terminated system. Standard installation for both types of cables in data centers too has not worked. All types of installations have been tested in practice and measured at different times during install.
Methods for searching and documenting optical cables
Havliš, Ondřej ; Křepelka, Václav (referee) ; Filka, Miloslav (advisor)
The purpose of this bachelor thesis is a description of searching for optical cables with metallic elements and EMS markers below the earth surface by suitable method and the possibility of recording and documentation of optical cables in a geographic information system ArcGIS. In the beginning there is a mention of an optical cable in particular of its the most important part, which is an optical fiber. Further there is the purpose what the optical fiber in the telecommunications world of techniques was developed for. Then there are the various advantages of the optical fiber described. This project also deals with the various methods of searching the optical cables using metallic elements. It is a called Galvanic and Inductive method, which are used to search for the optical cable by using the enclosed metallic lines, which, with the proper connection to a receiver, generates electromagnetic fields around. Another way to search the fiber optic cable is realized by the EMS markers. There are various types of passive electronic tags described. These electronic passive tags are manufactured in different color, which is used for marking the various branches of networks. There is the possibility of documentation of the optical cables by using ArcGIS geographic system from ERSI mentioned in the project. There is its structure and func-tion of individual subprograms in detail described. In the chapter GSM there is an analysis of operating principle of the system. At the end of this thesis the laboratory task is suggested. It describes the searching for fiber optic cable and the other metallic circuits by passive markers and iD markers.
Software based optical cable documentation
Martínek, Michal ; Křepelka, Václav (referee) ; Filka, Miloslav (advisor)
The focus of this work is a description of search-optic cables and cables stored in the Earth's surface suitable method and the possibility of registration of the optical paths and components in the ArcGIS geographic information system. The work set out in detail the different types of optical fibers and principles listed in the wiring examples most commonly used cables. There are additional elements used in the construction of optical networks, whether the individual connectors, hubs, etc., as well as protection features most often used for distribution of optical cables. There are also examples given options stowages routes and laying cables, and most currently with the possibility to discover a practical listing and description of these search engines non-metallic elements. The work also focuses on how these elements efficiently record to go to them quickly and easily access and simplify their close location in real space, to ensure unwanted destructive interruption, or any repair, expansion, etc.
QoS implementation in access network
Hauser, Václav ; Křepelka, Václav (referee) ; Filka, Miloslav (advisor)
My bachelor thesis deals with the implementation of quality of service in the access network. My bachelor thesis describes at first the concept of quality of service and its characteristics. In addition, it makes the reader familiar with various implementations models. At first with integrated services, which are based on the RSVP reservation protocol. The task of this protocol is to establish the route through the reserve RESV and PATH messages. The second implementation model contains the differentiated services. There is no reservation protocol, quality of service is ensured by using the classification of individual data flows. Accordingly, as packets are classified, they are assigned according to a priority, which is crucial for the packets travel through the network. Next part of this thesis describes the implementation of any different types of configuration of two implementation models of quality of services. There is configuration of RSVP protocol, MQC, AutoQos and MLS QoS. Final chapter describes the configurations examples.
Assemblying effect on cable lines quality
Dočkal, Martin ; Křepelka, Václav (referee) ; Filka, Miloslav (advisor)
In the first part is explained what actually a structured cabling is. Its beginning, from what and why it was created. Its history when at the beginning were applied unbalanced coaxial cables, those were later replaced by balanced cables. In cabling for TVs are still used coaxial cables. Balanced cables are according to type named UTP, STP, FTP, and so on. Whit growing popularity of this type of cabling and its wide spread application was necessary to set some rules, standards, specifications and demands, how to build up the cabling from project to realization. According to these rules is the system built so there are strict rules for length of subsystems and interfaces and the whole appearance of the structure cabling. Next important point is projecting of cabling that is related to the previous points and when it’s finished, we should strictly follow it. With the project is closely connected characteristic of this cabling as attenuations, cross-talks and other transmission parameters which are measured in the practical part. In the second part is spoken about all the parts of which the structured cabling consists - metallic and optical connecting elements and cables. There are also mentioned their mechanical, electrical and transmission features. In the third part is described influence of man on the quality of structured cabling and the most common causes of lower quality and the ways how to prevent this from happening and how to manipulate with cabling not to destroy it. The final (fourth) part considers the measurement. There are measured qualities of metallic wires as the attenuations, delay, cross-talks on the near- and far-end, impedance and resistance. To all the features are mentioned schemes of the measurement on the twisted pairs. The measurement is divided into two parts. In the first part are measured five types of balanced cables of different length, category and damage influencing quality of these cables. In the second part is measured one balanced cable if it’s corresponding with category 5 for that t was made and if it would be possible to use it also for higher category 6. Values are tabularly sorted in tables.
Influence of optical connectors and of other effects on optical link attenuation
Winkler, Aleš ; Křepelka, Václav (referee) ; Filka, Miloslav (advisor)
In this time the metalic wires meet not the requirements of high capacitance and rate wire and so the new, modern fiber wires are more and more being used. This bachelor`s thesis deals with three basic kinds of connections of fiber wires, optical connector, mechanical coupling a optical weld, and their effect on optical link attenuation realized by fiber optics. The optical link is possible realized number of kinds fiber optics. In this thesis are most often used multimod and a little multimod fiber optics. By mechanical coupling are explored their effects of attenuation on optical link a their detrition after disconnection and next connection back to the optical line. For optical weld is explored quality assignet optic welder. For optical connectors is explored their quality of cleanness through apparatus OTDR( Optical Time Domain Reflectometer) and geometrical properties through apparatus FIBO 250.
DSL-based triple-play services
Al-Anqari, Mhannad ; Křepelka, Václav (referee) ; Šilhavý, Pavel (advisor)
This research examines the triple play service based on the ADSL technology. The voice over IP will be checked and combined with the internet data by two monitoring programs in order to examine the performance that this service offers and then will be compared with the usual method of internet connection.
The Design of FTTH Network
Zorgani, Nagib Youssef ; Křepelka, Václav (referee) ; Filka, Miloslav (advisor)
The aim of this thesis is to explain the problems of optical access networks with wavelength division multiplexers, main purpose is to demonstrate the difference between theoretical and real measurement. The work is divided into several thematic areas. The introduction outlines the basic of telecommunications, fiber optics lasers, single mode, multimode, lasers fibers cables & cores, splitters division multiplexing system, there are known solutions discussed fundamental wavelength multiplexes and their possible combinations. The following chapter deals with the active elements such as AON, PON, which are essential part xWDM systems such as optical lasers, detectors and amplifiers. Another chapter focuses on passive elements, which form a key part of the wavelength multiplex. Methods of measurement of WDM/PON networks are discussed in the following part. The next section describes the topology used active and passive optical networks. The penultimate part of the work consists of architecture & technology of xWDM such as GPON and WDM-PON networks and comparing their transmission parameters. The final part of the paper presents the results of practical experimental measurements of optical access networks with wavelengths division multiplex while these results are compared with the theoretical output & methods of Optical lost test, OTDR & LSPM, with advantage & disadvantage of every methods. The second part of practical is the draft to the connection resident housing units of 30 houses, boarding-house (10 rooms) and 2 shops, 20 km distant from exchange. With comparing the possibilities of two options- passive and active optical network- PON system – WDM- Wave multiplex. Suggest the possibility of measuring and monitoring the created network.
Bragg gratings in optical fibers
Urban, František ; Křepelka, Václav (referee) ; Filka, Miloslav (advisor)
Thesis focuses on the principles and properties of the tilted Bragg fiber gratings. Two models of the principal cladding mode behaviour are proposed and ther respective results compared with experimental data. The experimental setup for the preparation of the tilted gratings is described. The thesis shows the evaluation of the gratings parameters for the set of prepared gratings. Application of the tilted gratings in the sensors is discussed

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