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In 1940, the first communication system relied on coaxial cable that operated at 3 MHz and could carry 300 telephone conversations or one television channel. Additionally, electrical signals can interfere with each other when the wires are spaced too close together, a problem known as crosstalk. But the bandwidth of copper is limited by its physical characteristics-as the frequency of the signal increases to carry more data, more of the signal's energy is lost as heat. Circulator, to tie in other components, such as an OADM.Īt its inception, the telecommunications network relied on copper to carry information.Optical splitter, to send a signal down different fiber paths.Optical switch, to direct light between ports without an optical-electrical-optical conversion.These can include Optical Add/Drop Multiplexer (OADM) and Reconfigurable Optical Add/Drop Multiplexer (ROADM). Multiplexer/demultiplexer, also called mux/demux, filter, or prism.

to link LANs on a campus.Ĭomponents of a fiber-optical networking system include: įree-space optical networks can also be used to set up temporary terrestrial networks e.g. Airborne optical networks between high-altitude platforms are planned as part of Google's Project Loon and Facebook Aquila with the same technology. Several planned satellite constellations such as SpaceX's Starlink intended for global internet provisioning will use wireless laser communication to establish optical mesh networks between satellites in outer space. Another variant of fiber-optic networks is the passive optical network, which uses unpowered optical splitters to link one fiber to multiple premises for last mile applications.įree-space optical networks use many of the same principles as a fiber-optic network but transmit their signals across open space without the use of fiber. Anna University Regulation 2017 Electronics and Communication Engineering ECE Important questions.The most common fiber-optic networks are communication networks, mesh networks or ring networks commonly used in metropolitan, regional, national and international systems. Electronics and Communication Engineering ECE Regulation 2017 Important questions Anna UniversityĮlectronics and Communication Engineering ECE Regulation 2017 Important questions Anna University pdf free download.