2.1 TYPES OF DIGITAL COMMUNICATION Flashcards
WHAT IS SATELLITE COMMUNICATION?
Transmits data and radio waves. Receives data from digital devices.
HOW DO DIGITAL DEVICES RECEIVE RADIO SIGNALS?
Digital devices use antennae to receive radio signals that satellites transmit.
WHAT ARE THE 4 USES OF SATELLITE COMMUNICATION?
- GPS
- TV
- Telephone
- Military
HOW IS SATELLITE COMMUNICATION USED FOR GPS?
Navigation aids make use of GPS signals to calculate the exact location of a device.
HOW MANY SATELLITES ARE ON EARTH AND HOW ARE THEY CONNECTED TO US?
24 satellites on earth. 12 in your range. 4 needed to locate.
HOW IS SATELLITE COMMUNICATION USED FOR TV?
Video signals from broadcaster is transmitted through large antennae on earth to multiple satellites. Then the satellite broadcasts this signal back to earth. Set-top box deals with the rest.
WHAT DOES A SET TOP BOX DO?
Decodes signal and converts it so it is ready to be sent to TV.
HOW IS SATELLITE COMMUNICATION USED FOR A TELEPHONE?
People in rural areas make calls using satellite telephones.
HOW IS SATELLITE COMMUNICATION USED FOR THE MILITARY?
The military use satellites for communication systems like global demand and control system.
BENEFITS OF SATELLITE COMMUNICATION?
The system is always available because of the number of satellites.
DRAWBACKS OF SATELLITE COMMUNICATION?
- Satellite signals do NOT pass through objects so it will not work in areas with tall buildings/tunnels.
- Can be affected by weather.
WHAT IS BROADCAST COMMUNICATION?
Transmitters broadcast radio waves, TV signals, radio signals that are received by viewer’s antennae. Antenna sends signals through wire to TV/radio receiver which then converts it into image/audio.
WHAT IS WIRED COMMUNICATION?
Uses cables to connect with each other, only uses electrical signals.
WHAT ARE THE CONNECTION TYPES OF WIRED CONNECTION?
- HDMI
-S/PDIF
-MINI JACK - USB
- ETHERNET
WHAT IS HDMI USED FOR?
Used for digital video connection.
WHAT IS S/PDIF USED FOR?
Used for digital audio connections.
WHAT IS MINI JACK USED FOR?
Personal headphones.
WHAT IS USB USED FOR?
Storage transfer
WHAT IS ETHERNET USED FOR?
Used for networking
WHAT IS ETHERNET?
Ethernet is network connectivity, providing a standard way to communicate for computers.
WHAT IS WIRELESS COMMUNICATION?
Uses wireless radio waves connectivity to communicate to each other.
WHAT ARE THE WAYS OF WIRELESS COMMUNICATION?
- Wifi
- Bluetooth
- 3G +4G
- Infra-red (IR)
- Near-field communication (NFC)
WHAT IS WIFI AND HOW IS IT USED?
WIFI is wireless technology connecting devices to a network. The network itself is connected to the internet.
FEATURES OF WIFI?
- Long range
- High bandwidth
- High power
- High security
- Can connect multiple devices simultaneously
WHAT IS BANDWIDTH?
Number of bits that can be carried by a connection in one second.
WHAT IS BLUETOOTH?
When devices connect over small distances.
FEATURES OF BLUETOOTH?
- Short range
- Low bandwidth
- Low power
- Low security
- Connects limited devices simultaneously (usually has to be paired)
WHAT DOES 3G+ 4G DO?
Provides internet access to mobile devices when WIFI signal is not available.
FEATURES OF INFRA-RED?
- Devices connect over short range
- Transmitters need to have a clear line of sight to receivers. Nothing can block the signal to the receivers, HAS TO TRAVEL IN STRAIGHT LINE.
WHAT DOES NEAR-FIELD COMMUNICATION (NFC) DO?
Uses close proximity RFID (Radio Frequency Identification) chips (in SIM/credit cards).
WHAT IS DEVICE-TO-DEVICE COMMUNICATION?
Wired/wireless connection between multiple devices.
EXAMPLES OF DEVICE-TO-DEVICE COMMUNICATION?
- Phone + headphones –> minijack = audio played from phone to headphones.
- Camcorder + monitor –> HDMI = operate as security camera.
WHAT ARE THE NETWORKS DIGITAL DEVICES CONNECT OVER?
- Local Area Network (LAN)
- Wide Area Network (WAN)
- Personal Area Network (PAN)
- Tethering
HOW DOES LAN WORK?
LAN connects digital devices in a small geographical area - close together.
HOW DOES WAN WORK?
Network spreading over a large geographical area. Connected over many satellites (many LANs). Distance issue - can be connected directly.
USES OF WAN?
- National and international businesses
- Law enforcement agencies
- Health and education organisations
- Government departments
HOW DOES A PAN WORK?
Group of connected devices all near to an individual user.
EXAMPLE OF PAN?
Connecting a smartwatch to a smartphone.
HOW DOES TETHERING WORK?
Connecting to a host device that uses mobile broadband connection with one or more devices. Lets other devices connect easily. Can be tethered wired/wireless.
