Other Stuff I Missed Flashcards
(32 cards)
What are the three types of Classical Ciphers?
Transposition
Substitution
Product
What are the two types of Modern Ciphers?
Block
Stream
TDR Open Circuit V-t diagram
TDR Short Circuit V-t diagram
TDR Resistive Load V-t diagram
TDR Parallel RC load V-t diagram
What are three main factors for determining the type of orbit?
Alititude
Orbital period
Inclination
How does a Molniya orbit affect the coverage of a satellite?
Allows the satellite to spend more time over a specific area of highest apogee. It also allows higher orbits which provide greater coverage.
What is the most common orbit for communication satellites and why?
GEOstationary orbit because it allows them to remain fixed over a position for consistent coverage.
Why is there a restriction on frequencies used by satellite systems?
Prevent inteference between different satellite systems.
What is COMMPLAN
Describes comms strateg6y, protocols, procedures to be employed.
Describe two technological developments related to telephone exchanges
Digital switching - converting to digital data
Electronic switching - evolution from manual switching, allowed complex networks
Why would a home satellite television dish not require an Antenna Controller Unit
Connects to GEO satellites
What frequency range for satellites and why
1-40 GHz because lower frequencies can penetrate atmospheric layers with less attenuation but higher frequencies can carry greater bandwidth.
What are 4 basic types of telephone exchanges
Local exchange - First point of contact for local users
Tandem Exchange - Connect local exchanges to eachother
Toll Exchange - Long distance calls between countries or cities
International Gateway Exchange - International calls
What is Quality of Service and 4 components
Performance of a communications network in terms of
Bandwidth
Latency
Jitter
Error
What are 5 frequency bands for radio communications
VHF
UHF
HF
SHF
EHF
What type of polarization is used for Satellite Communications and why?
Circular because it is not as reliant on receiver and transmitter orientation.
What is receiver sensitivity. If you had a receiver with -100dB and with -75dB, which would you use and why.
The minimum input signal pwoer required for the receiver.
You would use the -75dB receiver.
What is a leased line?
A dedicated line that provides constant, fixed BW connections.
What is a PSTN line?
Public Switched Telephone Network.
Shared network that routes calls through switches. Subject to variable traffic.
What is a mixer in a Direct Conversion Receiver. Also what is a Direct Conversion Receiver
DCR is also known as a homodyne receiver. Similary to superheterodyne except it converts incoming RF directly to baseband without an intermediate frequency. This allows a simpler receiver design but less flexible.
The mixer is the component that actually mixes the two frequencies to produce the baseband.
