Telephone, Radio, and Television Flashcards
What is an Electret?
A material with a constant electric charge.
What is an Electret microphone?
A type of microphone that uses an electrically charged membrane mounted on an electret.
What is a Speaker Cone?
A thin membrane in the speakers of a telephone.
What is Atmospheric Transmission?
The passage of an electromagnetic wave through the atmosphere between a transmitter and a receiver.
What is Physical Transmission?
Transmission of signals by wires.
What is a Diode?
A device used to convert alternating current.
What is a Transceiver?
A transmitter or receiver.
What is a Cell?
The area covered by each antenna.
What is a Carrier?
A wave that can be modulated to send a signal.
What is a Modulate?
The changing of a wave’s amplitude or frequency to send a signal.
What are the two types of Modulation?
AM and FM.
What is Line-Of-Sight Transmission?
The ability of high frequency transmissions to only be carried by simple straight lines.
What does AM stand for?
Amplitude modulation.
What does FM stand for?
Frequency modulation.
What are Ground Waves?
Waves that follow the curvature of the Earth for some distance.
What are Sky Waves?
Sky Waves are waves that spread out from antennas into the sky and are reflected in the upper atmosphere, which contains charged particles.
What is a Tuner?
A device that adjusts antennas.
What is a Cathode-Ray Tube?
A tube that uses an electron beam to create a display on a phosphorescent screen.
What is a Pixel?
The smallest element of a display image.
