telecommunication Flashcards
identify the process of sending more than one signal
multiplexing is the process of sending more then one signal down the wire.
The transmission of information by electromagnetic radiation depends on the process of… ?
Modulation of information is required for transmission by electromagnetic radiation
Identify the name the instrument to determine the usable frequencies of the ionosphere
The I_onosonde_ is the name of the radar used to determine the usable frequencies
Communication satellites orbit in … ?
Communications satellites orbit the earth in geostationary orbits.
The periodic amplification of optical fibre signals is required due to
Dispersion of the optical signal
identify the alternative term for an analogue signal
A continious wave
identify the three types of radio propagation
sky wave, direct wave, ground wave
compare the benifits of FM over AM radio
- less susceptible to noise and interference
- greater frequency response
- higher fidelity
discuss the advantages of satellite communication systems
the path of a radio signal refracted from the ionosphere and the signal hop length are illustrated
discuss the advantages of digitisation
- high fidelity
- time dependence
- signals may be coded
discuss the use of copper alloys in data transmission
- copper has high electrical conductivity
- is easily drawn into wires
- can be cold worked to obtain a relatively high strength
what does AM and FM stand for ?
AM -amplitude modulation
FM -frequency modulation
define bandwidth
bandwidth is the diffrence between the upper and lower frequencies of a band of electromagnetic radiation. it is sometimes used to describe the ammount of information that can be transmitted over a communication channel within a peroid of time
What is a carrier wave
A carrier wave is an electromagnetic wave that can be modulated as in frequency, amplitude or phase to transmit information.
what is fibre optics
fibre optics is the transmission of light signals via optical fibres
what is a optical fibre
A optical fibre is a thin fibre made of glass that functions as a waveguide for light by the total internal reflection and used to convey information
define dispersion
dispersion is the act or process of scattering. in optical fibres, interactions with impurities in the glass lead to dispersion of the light.
what is a multiplexer ?
a multiplexer is a device that can interleave two or more activities. it allows more than one message to be sent over a communication channel at the same time
explain what is ment by the term channel in telecommunications
A channel is any path by which a communication may progress from a transmitter to a receiver and can consist of a physical link such as wire or cable or a non-physical link such as electromagnetic radiation
what is a sky wave ?
a sky wave is a radio wave that is refracted back to earth by the ionosphere or a communications satellite, it permits transmission around the curve of the earths surface
