9.1 Communication Flashcards
Symbol
Particular pattern of bits represented by a signal
Baud Rate
Number of signal changes in the medium per second in a communication system
Bit rate
Number of bits that are transmitted over a medium per second.
Bit Rate Calculation
Bit Rate = Baud Rate x No. of Bits Per Signal
Bit Rate > Baud Rate
More than one bit is being sent per signal.
Bandwidth
Range of frequencies that a communication system is capable of transmitting.
Unit of Bandwith
Hertz
Direct positive relationship between bandwidth and ____
bit rate
Latency
Difference in time between an action being initiated and its effect being noticed. Measured in milliseconds.
Protocol
Set of rules relating to communication between devices.
Serial Data Transmission
Data is sent one bit at a time over one communication line.
Use for serial data transmission
Transmitting data over medium to long distances
Parallel Data Transmission
Data being sent multiple bits at a time through numerous parallel communication lines simultaneously.
The more lines a parallel communication medium uses…
The more data can be transferred
Skew Definition
Each of the communication lines have different electrical properties meaning the time taken for a bit to be transferred will vary slightly and be received at different times.
Problems with Parallel Data Transmission
- Skew is worst over long distances
- Skew can cause corruption of data because pulses overlap
- Parallel communication mediums are more expensive than serious communication
- Cross Talk
- More expensive
Cross Talk
Where signals from one line leaks into another because they’re packed closely together, causing data corruption.
Synchronous Transmission
-A clock signal is used to time when signals are sent.
-Used within the buses of a computer’s processor in Fetch-execute
- The signals are sent at regular intervals
- Signals received in the same order
- Useful for realtime systems
