is a continuum of electromagnetic waves
arranged according to frequency and
wavelength.
EM Spectrum
According to increasing frequency, the EM
spectrum includes:
radio waves, microwaves,
infrared, visible light, ultraviolet, X-rays and
gamma rays.
have longest wavelengths
in the EM spectrum. low freq
used to transmit radio and
television signals.
have wavelengths that range
from less than a centimetre to tens or hundreds of meters.
Radio Waves
AM- Amplitude Modulation
FM- Frequency Modulation
___ has higher frequency
FM
In ___, radio wave known as the
“carrier” or “carrier wave” is modulated
in amplitude/frequency by the signal that is to be
transmitted. The frequency/amplitude and phase
(audio signal) remain the same
AM- amplitude
FM- frequency (same w FM)
AM has poorer sound quality
compared with FM, but is
cheaper and can be transmitted
over long distances. “stored”
FM is less prone to interference
than AM
true
what are the applications of radio waves
Radio navigation,
Radio communication,
air craft beacon,
weather systems,
Non-directional navigational radio beacons,
Normal range of human speech,
Radio and satellite communication
application:
Radio navigation
Radio
communication,
air craft beacon,
weather systems
Radio Waves
the application of radio frequencies
to determine a position of an object
on the Earth.
Radio Navigation
uses AM-radio transmitters
operating in the low and middle
frequency band
Automatic Direction Finder (ADF)
A _____
system sends signals by radio.
Radio
technology of using radio
waves to carry information such as sound
radio communication
Air Traffic Control
prevent collisions,
organize and expedite the flow of
traffic, and provide information and
other support for pilots.
true
a radio transmitter at a known location, used
as an aviation or marine navigational aid.
_____ provide a charted, consistent
method for defining paths aircraft can fly.
commonly used as markers or
“locators” for an instrument landing system
Non-Directional Beacon
NDB bearings
◦It is mainly done through geostationary
satellites.
◦ These devices can receive signals
from Earth station and transmit them again in different directions. These are
called ______.
designed to transmit and receive signals from a
satellite in orbit around the Earth.
Satellite Communication
transponders
The area which receives signal from the satellite is known as the
The transmission system from the
earth station to the satellite is called the
The transmission system from the
satellite to the earth station is called the
satellite’s
footprint.
uplink earth station.
downlink.
________ transmits signals in the form of (EM) waves. These waves carry audio
(sound) or video (picture) messages. The satellite
receive these waves.
send in the form of high-powered, high
frequency signals to satellites that receive and
retransmit signals back to Earth.
◦Earth station
extremely high
frequency radio waves.
short wavelengths
found between high
frequency infrared waves and conventional radio waves.
Microwaves
is considered an active remote
sensing system because it actively sends a
microwave pulse and senses the energy reflected
back.
Radar technology
transmission of waves at microwave frequencies
and then detecting its echo after reflection from
a distant object
Radio Detecting And Ranging
◦A radar tracking system using the Doppler Effect to
determine the location and velocity of a storm, clouds,
____change in the observed frequency
of a wave.
Doppler Radar
Doppler Effect
◦A radar which is designed to make measurements of
the echoes from ocean and ice surfaces.
Radar Altimeter
is a device used to measure the
speed of moving objects.
◦ It is used in law-enforcement to measure
the speed of moving vehicles.
Radar Speed Gun
is an electron tube
for generating microwaves.
Magnetron
____ discovered in
1800 the existence of infrared by
passing sunlight through a prism.
Sir William Herschel
