Communication Flashcards
What is a symbol
A particular pattern of bits represented by a signal
What is a Baud rate
The number of signal changes in the medium per second
What is the Bit Rate
The number of bits that are transmitted over the medium per second
Equation for Bit Rate
Baud Rate x # of bits per signal
When will a communication mediums bit rate be higher than its Baud Rate
If there is more than one bit sent per signal
What is Bandwidth
The range of frequencies that a communication medium is capable of transmittign
What is the relationship between Bandwidth and Bit Rate
Direct Relationship
What is Latency
The difference in time between an action being initiated and its effect being noticed
What is latency measured in
Often in milliseconds
What increases with distance
Latency
What is a Protocol
A set of rules relating to communication between devices
What are the two ways computers can transmit data between different components
Serially
Parallel
Describe Serial Data Transmission
Data is sent one bit at a time over one communication line
Frequently used for transmitting data over medium to long distances
Describe Parallel Data Transmission
Multiple Parallel Communication Lines are used
Multiple Bits are sent between components in a computer simultaneously
What is skew
Bits that are sent together may not be received together
Why is parallel data transmission is most often used over short distances
Skew is worst over long distances - Pulses overlap causing corruption of data
Parallel communication mediums are more expensive than their serial counterparts due to their multiple lines
Crosstalk can occur
What is crosstalk
When signals from one line leak to another causing data corruption
Describe Synchronous Transmission
A shared clock signal is used to time when signals are sent
Signals are sent at regular intervals and are received in the same order that they were sent
When is synchronous data transmission often used
Within busses in the fetch execute cycle
Transmission information in real time systems
Describe asynchronous transmission
No need for shared clock signal - start and stop bits are used
Stop bit is always opposite to the start bit
Sender and receiver must use the same Baud rate
Only need to synchronise their clocks for the duration of data transmission
