1. Wireless Communication
EQ: How are radio waves used to transmit information?

2. EQ: How are radio waves used to transmit information?
Television, radio, cell phones, pagers and cordless telephones all rely on radio waves to work
Each of these are assigned a frequency by the FCC. This means the radio wave piece of the ems is divided into bands that are assigned for different purposes
EQ: How are radio waves used to transmit information?

3. EQ: How are radio waves used to transmit information?
AM Radio
EQ: How are radio waves used to transmit information?
Stands for amplitude modulation
Frequency of the radio waves are constant
At the broadcasting station, music and speech are converted from sound waves to electronic signals
The signals are then converted into a pattern of changes in the amplitude of a radio wave
Next, your radio picks up the signal and converts it back to a sound wave

4. EQ: How are radio waves used to transmit information?
AM Radio
AM radio waves have relatively long wavelengths and are easily reflected by the earth’s ionosphere
Ionosphere is the electrically charged layer of the earth’s atmosphere
The AM radio frequencies
ability to bend allows it to
“bend” around the earth’s
surface and to travel farther

5. EQ: How are radio waves used to transmit information?
FM Radio
Frequency Modulation –
FM signals travel as changes
in the frequency of the wave
FM frequencies are much higher than AM
Instead of reflecting off the ionosphere, FM radio waves penetrate the atmosphere because of their higher frequency (which means they have more energy)
This is also why FM waves do not travel as far as AM waves

6. EQ: How are radio waves used to transmit information?
Television
Television broadcasts similar to radio but they travel on VHF (very high frequency) radio waves and UHF (ultra high frequency)
EQ: How are radio waves used to transmit information?

7. EQ: How are radio waves used to transmit information?
Cellular Phones
Transmit and receive signals using microwaves
Areas divided into small cells (cell towers)
They cannot travel far, that is why we have so many towers
EQ: How are radio waves used to transmit information?

8. EQ: How are radio waves used to transmit information?
Pagers
When you leave a message for a pager, your message is sent to a receiving station.
Then the message is coded and sent to the correct pager
The pager then beeps or vibrates to let you know you have a message

9. Communication Satellites
Radio waves are sent from earth up to a satellite, which then relays the radio waves to other receivers on earth
EQ: How are radio waves used to transmit information?

10. Communication Satellites
We need these so we can communicate around the world because radio waves cannot travel through the earth
EQ: How are radio waves used to transmit information?

11. EQ: How are radio waves used to transmit information?
GPS
Global Positioning System
Uses a group of 24 satellites that work together to transmit and receive radio waves
Originally used only in the military
EQ: How are radio waves used to transmit information?

12. Class Work and Homework
EQ: How are radio waves used to transmit information?
Fill In
What did I learn
Confused
Say
Read pages O96 – O103, Questions1-5