Radio frequency digital and analogue signals, that until recently were transmitted through copper cables (coaxial cables), today are increasingly being replaced with optical fibre cables transmission.
Advantages of the optical access network are primarily reflected in the bandwidth, quality and data transfer rate. The bandwidth provides low attenuation with optical fibre cable, an appropriate light source and optical detector. Quality of the optical fibre cable transmission is substantially higher because the optical fibre cable is dielectric cable, i.e. electromagnetic interference (lightning, crosstalk between individual glass wires) does not affect the signal. Capacity of the optical fibre amounts to approximately 10 THz bandwidth that is available to the optical fibre and that can be used for communication purposes. From this aspect, the optical fibre is the best bandwidth medium.
The subject thesis deals with the optical access network with DVB-C technology, focusing on two architectures. The first one is DVBC-P2P, that provides a direct optical connection between the user's modem and the central station. The second architecture is DVBC-GPON where a single optical fibre, using fibre optic splitters, is connected with multiple customers.
In the practical part of the thesis, we have presented in more detail the design of the optical network, i.e. the connection of optical fibres with fixed welded connection or connectors, preparation of optical couplers for protection of welds, attenuation measurement, preparation of signals from different sources, conversion of RF signals to optical network signals and vice versa as well as intensifying of optical signals.
We will present the essential characteristics of quality transmission of DVB-C signal to the end user with two different architectures, which is also the main objective of our thesis.
The challenges we were facing during the performance of the practical part of the thesis were related primarily to the network building design, provision of welding and measuring equipment and real-time fixing of defects on connections and connectors.