Radio Transmissions
Define carrier wave
What is an electromagnetic wave with a frequency that has been assigned to a station.
Define digital signal.
What is an electric signal with only on/off values.
Define transceiver.
What is a device that can transmit and receive radio signals.
Most satellites are used for this.
Define Global Positioning System. (GPS)
What is a system of satellites, ground monitoring stations, and receivers that determine your exact location on or above Earth's surface.
True or False: All stations do is transmit carrier waves.
What is False, they also send information about the sounds being sent to you.
Digital signals started being sent to TV stations in the U.S.A. this year.
What is 2009.
Describe what would happen if you were using a cordless telephone, and someone close to you was also using one.
What is you would hear their conversation.
Explain why satellite receivers are dish-shaped.
What is to focus the microwave on the antenna.
The number of satellites used.
What is 24.
Name two ways you can modulate carrier waves.
What is AM or FM.
Information sent through FM and/or AM.
What is audio and/or visual.
How far apart are microwave towers and what area do they cover?
What is a few kilometers and each covers an area called a cell.
Why are microwaves used for TV satellites?
What is they travel more easily through the atmosphere and have short wave lengths.
The number of satellites needed to find the location of a receiver.
What is four.
Name what is changed in an AM and/or FM radio.
What is frequency and/or amplitude.
TV stations are modulated using these.
What is Amplitude-Shift Keying or Frequency-Shift Keying.
Describe what can happen if your phone comes close to a pager someone else is using.
Your phone can interfere with the waves being sent from the pagers.
Describe how a satellite broadcasts signals.
What is the satellite amplifies that signal and sends it to a part of Earth in a different frequency that it was broadcasted to.
True or False: Anyone can use GPS.
What is true.
Describe how radio waves are received.
What is electromagnetic waves pass by the radio antenna, causing the electrons in the antenna to vibrate. This creates a changing electric current consisting of information on the music and words. This makes the speakers vibrate, resulting in the sounds you hear.
Modulating signals in a complex way allow this.
What is more information is carried with one wave.
Compare speaking into a cordless telephone and a cell phone.
What is when you speak into the microphone of a telephone, the microphone converts the signal waves into an electric signal. In a cell phone, the signal is transmitted to and from microwave towers through microwaves or radio waves.
Explain how a satellite receives and broadcasts signals from someone in the ocean.
What is mobile telephones being used at sea send their signals directly to satellites, since there are no cell towers. The satellite sends the signal to a ground station.
What is GPS used by?
What is phones, planes, cars, and pet collars.