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Communication Terms
Definitions
Question | Answer |
---|---|
Frequency | the number of waves to pass a point in one second |
Frequency Modulated | the frequency of a carrier radio wave which is modified to carry broadcast information |
Geostationary Satellite | satellite held in a fixed position in orbit above earth |
Graded Optical Fibre | optical fibres which are more optically dense towards the centre and less optically dense towards the edge of the fibre |
Hertz | measurement of frequency; the number of waves to pass a point in one second |
High Earth Orbit | geostationary satellites are placed in High Earth Orbit 36000km above the Earth's surface |
Impulse | short burst of energy |
Incident angle | The angle between the normal and the entering light beam |
Information System | way of transferring information from place to place that used energy |
Infra-Red | waves of the electromagnetic spectrum with wavelengths ranging from 700nm to 1nm |
Internet | worldwide computer networks linked through telecommunication lines and electromagnetic waves |
Ionosphere | ionised region of the atmosphere extending about 1000 km above Earth's surface |
Kinetic Energy | movement energy |
Land Connected Telephones | telephones connected by landlines |
Aerial | Device for transmitting and/or receiving radio waves |
Amplitude modulated (AM) | The height of a carrier radio wave is modified to carry broadcast information; AM radio waves |
Analog | Information not coded as ons or offs or zeros and ones |
Antenna | Metal wire which detects radio waves |
Bandwidth | The range of frequencies over which an electromagnetic wave is transmitted |
Bar code | series of black and white lines containing code information representing the manufacturing country, the manufacturer and the item code |
Boosting | Using electricity to enhance a signal for better volume and clarity |
Cathode ray tube | vacuum sealed space where a beam of electrons is fired at a screen coated with phosphor |
Cladding | in terms of optical fibres; the material coating the optical fibre which is less optically dense than the core of the optical fibre |
Code | a collection of symbols used for communication |
C0der | Transforms information into a specific code |
Communication System Information transfer system. | Information transfer system. |
Compact Disc | Thin reflective metallic disc with tiny bits containing information for computers and/or stereos such as computer programs or music. |
Compact Disc Player Device for changing compact disc information into sound. | Device for changing compact disc information into sound. |
Compression | Part of a sound wave where the particles of matter are closest together. |
Constellation | A constellation is a series of satellites which together provide data cover of particular parts of the Earth. |
Crest | The highest point of a wave equal to the densest part of a sound wave compression. |
Critical Angle | The incident angle at which a beam of light will travel along the edge of an optically denser medium. |
Decoder | Transforms coded information into another form. |
Demodulator | Removes the carrier wave from the radio signal. |
Diaphragm | Vibrating membrane in microphone or speaker. |
Radio (receiver) | Device which tunes into specific AM and FM radio waves for information transmission |
Radio frequency amplifier | Boosts selected radio frequencies |
Radio telescope | Large dish-shaped object to reflect radio waves to a central point for collection |
Random Access Memory (RAM) | Where information is temporarily held electrically in a computer's memory |
Rarefaction | Part of a wave where the particles of matter are furthest apart |
Receiving Dish | Dish-shaped object that collects then reflects electromagnetic waves to a central point for collection |
Refractive index | Measure of ability of a material to bend light; the higher the refractive index the more bending of light occurs and the more likely it is that total internal reflection occurs |
Satellite | Object held in orbit around a body such as a planet due to gravity |
Satellite dish | Reflects electromagnetic waves to a receiver |
Short Waves (SW) | AM radio waves of short wavelength and high frequency that are reflected by the ionosphere and Earth and so used for overseas broadcasts |
Silicone | (in terms of fibre optics) a flexible layer surrounding an optical fibre and cladding for protection |
Small-diameter core | Optical fibre with a diameter small enough to fit only one light impulse at any one time |
Sound system | Plays music from compact discs, tapes or the radio |
Technophobe | Person with fear or dislike of modern technology |
Telecommunication | Any communication involving the use of connecting lines or electromagnetic waves over long distance |
Landline | Wires or cables used as communication links running above or below ground |
Larynx | Voice box containing vocal cords |
Line of sight | Unimpeded view between two points such as a transmitter and receiver |
Longitudinal | Waves that compress particles of matter, transferring energy in the same direction as the wave movement |
Low Earth orbit | Satellite orbit about 1000 km or less from Earth |
Magnetic strip | Strip on credit cards, key cards and travel tickets containing magnetically aligned digital information |
Mechanical waves | Waves that require a medium for transmission |
Medium Earth orbit | Satellite orbit about 10 000 km from Earth |
Megahertz | Millions of hertz |
Micrometre | One millionth of a metre |
Microwaves | Part of the electromagnetic spectrum from 1 mm to 30 cm in wavelength |
Mobile phone | Telephone using microwave transmissions for communication between transmitting towers and mobile telephones |
television (receiver) | cathode ray tube a screen attached to an aerial for radio wave reception; pictures appear on the screen due to the cycling of an electron beam across the screen. |
total internal reflection | reflection of light off the sides of a denser medium back inside the denser medium |
transmitting tower | tall tower which sends radio waves or microwaves for communication purposes |
transverse | the direction of energy movement is at right angles to the wave travel direction |
trough | the lowest point of a wave equal to the zone of lowest pressure in a sound wave |
tuner | electrical circuit device that selects specific radio wave frequencies |
uplink | electromagnetic waves transmitted to a satellite from Earth. |
vacuum | space containing no particles of matter |
verbal | using words (spoken or written or sign) as a code between sender and receiver |
video conferencing | teleconferencing using real-time video images over a monitor |
visible light | part of the electromagnetic spectrum ranging from 700 to 400 nm. |
wavelength | the distance from crest to crest or trough to trough on a wave. |
Modulation | adjustment of an electromagnetic wave so that it carries information |
Modem | abbreviation for modulator |
demodulator | device that changes digital signals from computer to analog signals that travel through copper ; also changes analog signals to digital so they can enter a computer |
Multimode optic fibre | optic fibre, the thickness of a strand of hair through which thousands of different digital transmissions may be sent |
Nanometre | one billionth of a metre |
Non - electronic | without use of electricity |
non - verbal | without the use of words (spoken or written or signed) |
Normal | ( in terms of optics) perpendicular to the surface of the interface between two mediums |
Optical/optically | involving light energy |
optical fibres | a strand of material (commonly glass fibre) through which light can travel |
orbit | an object rotating around another object in space due to the gravitational pull of the object with greater mass |
order of magnitude | measurement of size that uses power of ten; two quantities of the same order of magnitude have different but similar sizes |
photodiode | light sensitive diode that produces an electrical output on exposure to light |
polarising | (with regards to electromagnetic waves ) limiting the plane of the electromagnetic wave by eliminating waves in other planes |
polyurethane | (in terms of fibre optics a waterproof coating of an optical fibre |