30 Questions
What are the three types of networks mentioned in the text?
Wide-Area Networks (WANs), Metropolitan-area networks (MANs), Local-area networks (LANs)
Describe the characteristics of analog signals.
Analog signals are smoothly and continuously varying voltages or currents, typically represented by sine waves.
What differentiates digital signals from analog signals?
Digital signals do not vary continuously but change in steps or discrete increments.
What are some examples of devices that can be interconnected in a Local-area network (LAN)?
Personal computers (PCs), laptops, servers, and mainframe computers.
How are Metropolitan-area networks (MANs) typically implemented?
MANs are normally implemented with fiber-optic cable, though they may also use coaxial cable or wireless connections.
What services are provided by Worldwide fiber-optic networks?
Long-distance telephone and Internet services.
Who discovered a way to send people's voices across long distances in the 1870s?
Alexander Graham Bell
What did Alexander Graham Bell realize when one of the metal reeds on his device got stuck?
That the vibrating reed created changes to the electric current that passed through the wire.
When did Alexander Graham Bell receive a patent for the first telephone?
March 7, 1876
Who invented the Tesla coil, an important component of radio transmitters?
Nikola Tesla
In what year did Guglielmo Marconi send radio signals more than a mile through the air?
1895
Who was the first to transmit voice by radio?
Reginald Fessenden
What type of codes do most digital signals use?
Binary or two-state codes
What is an example of a single-frequency analog signal?
Sine wave
Give an example of an analog signal that varies in accordance with sound or light variations.
Voice and video voltages
Why must digital signals be converted to analog form to match the transmission medium in some cases?
To match the transmission medium
What is a common method used to transmit voice or video analog signals efficiently?
Digitizing with an analog-to-digital converter
How can analog signals be transmitted digitally?
By converting them to digital form
What is the main purpose of radar?
Detecting ships, planes, and missiles and determining their range, direction, and speed.
How is sonar used in underwater communication?
Audible baseband signals use water as the transmission medium.
What is the purpose of Amateur radio?
It is a hobby for individuals interested in radio communication, allowing them to build and operate two-way radio equipment for personal communication with other hams.
What is Citizens Band (CB) radio used for?
It is a special service for personal communication, often used in trucks and cars to exchange information about traffic conditions, speed traps, and emergencies.
What is Family Radio Service used for?
It is used for two-way personal communication with handheld units over short distances (< 2 mi).
How is the Internet categorized in terms of communication applications?
The Internet is a means of electronic communication that allows for various applications, including email, social media, and web browsing.
What is the main difference between simplex communication and half duplex communication?
In simplex communication, one device transmits and the others can only listen, while in half duplex communication, parties can both transmit and receive on the same frequency but not at the same time.
Explain why walkie-talkies use 'over' to indicate the end of transmission.
Walkie-talkies use 'over' to indicate the end of transmission to ensure that only one party transmits at a time, since both parties transmit and receive on the same frequency.
Why are half duplex systems usually used to conserve bandwidth?
Half duplex systems are used to conserve bandwidth because they require only a single communication channel that is shared alternately between the two directions.
What is a dual-simplex communication, and how does it differ from full duplex communication?
A dual-simplex communication uses two distinct channels, one for each direction, allowing each party to transmit on one channel and receive on the other simultaneously.
Can communications transmitted on any single frequency travel in both directions?
No, communications transmitted on any single frequency always travel in the same direction.
How can two-way radios be designed as full duplex systems?
Two-way radios can be designed as full duplex systems by transmitting on one frequency and receiving on another, known as frequency-division duplex.
Explore the differences between analog and digital signals in the field of Electrical Engineering. Learn about examples of analog signals like sine waves, voice, and video voltages, as well as examples of digital signals that use binary or two-state codes.
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