14-12-2012, 11:52 AM
LINK ENGINEERING
LINK ENGINEERING.pptx (Size: 505.42 KB / Downloads: 22)
A link in a communication system can be defind as connecting two point separated two distance , which one point act as transmiter & another point act as receiver…..
Data link are divided in four types
Wire line link
Radio wave link
microwave link
Infraed &millmetre waves link
WIRE LINE LINK
This wire line also know as guided media because the wave are guided along a solid medium , such as copper twisted pair , copper coaxial or optical fiber.
RADIO WAVE LINK
Radio waves are the electromagnetic waves. Radio waves are easy to generate , can travel long distance .
These waves are omi-directional means they can travel in all direction from source, so the transmitter and receiver .
PROPERTIES
Radio waves are frequency dependent. Low frequency radio waves easily pass through obstacles but the power of signal decrease sharply with increase the distance.
RADIO WAVE LINK
The electrical motors,generators,fans produce electromagnetic interference with radio wave
In VLF,LF,MF bends transmit radio wave of grond wave propagation.
The transmission range is1000 Km for low f/q.
DISADVANTAGE
It provide low bandwidth.
MICROWAVE LINK
Frequency in the range of about 1GHz to 30 GHz are referred to as microwave frequency.
CONSIDERATION FOR MICROWAVE LINK DESIGN
1. The microwave propagation path length is always longer then cellular propagation path.
2. The hight of path is always 30 metre to 50 metre above the ground.
3. The microwave transmission is a line of sight(LOS).
RADIO WAVE LINK
Radio waves are the electromagnetic waves. Radio waves are easy to generate , can travel long distance .
These waves are omi-directional means they can travel in all direction from source, so the transmitter and receiver .
PROPERTIES
Radio waves are frequency dependent. Low frequency radio waves easily pass through obstacles but the power of signal decrease sharply with increase the distance.