informatioin systems Flashcards
device for transmitting/and or receiving radio waves
Aerial
measurement of frequency; the number of waves to pass a point in one second
Hertz
another word for aerial
Antenna
What are longitudinal waves?
waves that compress energy in the same direction as the wave movement
A device used to increase sounds produced by a radio
ampliefied/amplifier
electrical circuit device that selects wave frequesncies
tuner
a device that finds and receives signals, separates and filters waves
detector
what do waves do ?
carry and transmit energy
waves can be measured in terms of ?
amplitude, frequesncy, wavelength
the information transfer process ?
code, encode,transmit(ter), decode(r)
OR
code, message, transmission, decoder
energy stored in chemicals ?
chemical energy
potential energy ?
energy that can be released later
movement meant energy is ?
kinetic
energy from differences in temperature
heat
light energy is ?
energy from a light source
energy released as traveling vibrations ?
sound energy
energy carried as waves at the speed of light ?
electromagentic
energy carried by electrons ?
electrical
energy coming from the sun ?
solar
nuclear energy is ?
energy released from converting mass into energy during fission or fusion
can energy be created or destroyed ?
no, just changed from one form of energy to another
what is it called when waves are reflected un all directions from an uneven surface
scattering (a special type of reflection)
sound waves can only be transferred by a ?
medium e.g air
can only travel short distances as ground waves, have a short wavelength
Microwaves
radio waves are a type of ?
electromagnetic wave
AM
amplitude modulated
FM
frequency modulated
guess the wave-
used for FM and AM radio, television, mobile phones, long waves such as military communication
Ground Waves
guess the wave-
is reflected by the ionosphere, used for short wave radio such as search and rescue, police, military and AM radio
Sky waves
guess the wave-
relayed by satellite, used for UHF and VHF television, international phone calls
Space waves
geostationary satellites are how high above earths surface ?
36,000 km, in a fixed position
a byte ?
are 8 bits
define analogue
an information transmission without on and off signals
bandwidth
the range of frequencies over which an electromagnetic wave is transmitted
cathode ray tube
- vaccum sealed space
- shoots electrons at a screen with phosphor
cladding
the material coating optical fibres
the carrier demodulator
removes the carrier wave from the radio signal
information systems
technology used for the purpose of communication
multiplexing
hold multiple signals
optical
involving light energy
polyurethane
waterproof covert of fibre optics
how do pictures appear on a television screen ?
due to the cycling of an electron beam across the screen