How is latency defined? What is the “Round-Trip Time”?
- The time it takes to transmit 1 bit of data from A to B
- The time it takes to send and receive an answer
How is the bandwidth defined? (strict sense, telecommunication)
Strict sense: The width of the frequency band. If the width is bigger, more data can be sent simultaneously. (Physical)
Telecommunication: How much data in a certain amount of time can be transmitted (10GB/s)
What is a “Baseband”? When is it used and what are its properties?
- (digital) Signal starts at 0Hz and uses the whole range it is called Baseband.
- Single , bidirectional channel
- Used for short distances
What is a “Broadband”? When is it used and what are its properties?
- Analog signal
- Transmissions use a percentage of the bandwidth but can be sent simultaneously
- Unidirectional channels (we need atleast 2 for sending and receiving)
- Big distances
Describe the coding of a signal from A to B.
Have a look at the image in the slides
What is a “backwards error correction” and what a “forward error correction”? And in what context is it used?
In the context of channel encoding.
- Backwards: Retransmission of packet
- Forward: Fix the faulty transmission
What is “Modulation”?
Signal or message to sent changes the frequency of the carrier medium.
What is “Multiplexing” and what is its usecase?
Multiplexing is e.g. used over fiber optics because they can only transmit one signal at a time. Multiplexing combines multiple signals into one by creating logical sub channels. Often also reffered as “mux” / demux
What are “guided” and “unguided” mediums?
- Guided: Wired cable
- Unguided: Wireless
Where to use Coaxial cabel?
- Better defence on radiation vs. Twisted pair cable
- Used for TV or connecting mobile antenna to ISP backbone
